JPH05200474A - Method and device for preliminarily forming die forging - Google Patents

Abstract

PURPOSE:To improve productivity by shortening processes. CONSTITUTION:This method uses a preliminary forming device in which an upper metal die 1 having a through hole 1a to insert a flank, an opposed mandrel 5 having a flank contact area 5a larger than the through hole 1a of the upper die 1, and a punch 4 that is inserted from above the flank 6 and vertically driven by a first driving device 8 are provided and in which a guiding part 5b consisting of a groove or an inclined part is formed on the flank contact area 5a. Then, the flank 6 is compressed between the punch 4 and the flank contact surface 5a, simultaneously, while the flow is guided by a guiding part 5b, the flank is allowed to flow out in a horizontal direction from the gap between the upper die 1 and the flank contact surface 5a, and an odd-shaped preformed product is formed. Thus, against products which are odd-shaped and highly nonaxisymmetric, the preliminary forming process is shortened and the productivity of the entire forging process is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for preforming a die forging product.

[0002]

2. Description of the Related Art Forging of aluminum has many advantageous conditions such as less scale generation and lower forging temperature than those of iron-based materials. Therefore, a member having a more complicated shape than steel die forging is used. The application is required, and manufacturers are realizing it. Since the history of aluminum forging has started as an aircraft part where there is a great demand for weight reduction, precision forging of complicated shape is required, and in the past it has been realized while accepting multi-step and low productivity. However, as the demand for aluminum forged products is directed to automobile parts, cost reduction is demanded as an alternative to conventional forged products.

For this reason, a new plastic working method is becoming necessary in order to remove from the poor material yield and low productivity of aluminum forging in the past. On the other hand, it is possible because of the superiority of hot working of aluminum. Is enough. By the way, in the case of an axially symmetric forged product, a material having various cross-sectional shapes is compressed in the axial direction so as to have a substantially rational metal flow and finally the material to be used in the cavity of the finishing die. Can be charged. However, in the case of a non-axisymmetric forged product, when the material is, for example, a columnar shape, a plurality of dies for rough terrain are used to obtain a preformed product having a rough shape, and further repeated forming is performed. It is necessary to gradually approach the final shape. Even if these multi-step molding steps are omitted and the cavity of the mold is filled with the material under an extremely large pressure, surface and internal defects such as lack of wall and cracks occur, and a sound product cannot be obtained.

Especially for a product shape having a high degree of non-axial symmetry, it goes without saying that the forging step is multi-step.
A trimming process for deburring is required in the middle.
Therefore, in the hot forging, the forging cannot be completed in one heat. As a result, the material yield and productivity, which greatly affect the product cost, are greatly deteriorated. The operation of giving a rough shape of the forged product having a non-axisymmetric shape by the above-mentioned rough mold is an operation of obtaining a preform having a material volume directionality and distribution adapted to the shape of the forged product, Also in the work of obtaining this preformed product, it is necessary to repeatedly apply molding using various molds and gradually bring it closer to the final shape. Has not been forged.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and the method of preforming a die forged product is configured by using rod-shaped raw materials having various cross-sectional shapes. An upper die having a through hole to be inserted, an opposing mandrel having a material contact surface that is larger than the through hole of the upper die and that faces the upper die with a predetermined interval, and the upper die. A punch which is inserted into the through hole of the mold from above the material and is driven longitudinally by a first drive device, the material contacting surface of the opposing mandrel being compressed by the punch. Using a preforming device that forms a guide part consisting of a groove and an inclined part that guides the flow of the material, compress the material to be inserted from the through hole of the upper die between the punch and the material contact surface of the opposing mandrel. While guiding the flow with the guide part of the material contact surface, Allowed to flow laterally from between the material contacting surface of the counter-mandrel, characterized by molding a preform which forms a variant. Then, the opposing mandrel can be provided with a second drive device that is driven in the vertical direction, and when forming the preform, the opposing mandrel can be moved in the vertical direction to change the wall thickness. In addition, the structure of the preforming device for the die forging product is such that an upper die having a through hole into which rod-shaped raw materials having various cross-sectional shapes are inserted and a material facing each other with a predetermined gap formed between the upper die and the upper die. A guide part including a groove, an inclined part, and the like for guiding the flow of the material to be compressed is formed on the contact surface, and an opposing mandrel larger than the through hole of the upper mold facing the material contact surface, and the upper metal. A punch that is inserted into the through hole of the mold from above the material and that is vertically driven by the first driving device. Then, the opposing mandrel can be vertically driven by the second driving device. Further, the opposing mandrel can be inserted into the through hole of the lower mold which is in close contact with the peripheral edge of the upper mold and defines a cavity between the upper mandrel.

[0006]

First, the material is put into the through hole of the upper die, the punch is lowered by the first driving device, and the material fitted into the through hole of the upper die is installed between the punch and the opposing mandrel. To do.
If the punch is further lowered to compress the material, the material is extruded laterally from the interval formed by the opposing mandrel having a larger diameter than the punch and the upper die, and laterally extruded to form a good metal flow. While diffusing into the cavity.

At this time, since the material contact surface of the opposing mandrel is formed with the guide portion including the groove and the inclined portion for guiding the material flow, the material is selectively divided and extended so as to have the irregular cross section. The material that has come out laterally from the material contact surface of the opposing mandrel is in light contact with the surface of the upper mold (and lower mold), the frictional resistance is reduced, and the material freely flows out.

By adjusting the plane shape of the opposing mandrel, the shape of the groove, the inclination angle of the inclined portion, etc., the material can be made to flow into each portion of the preform having the irregular cross section almost at the same time. In this way, since the flow toward each part of the material is freely flown out in the lateral direction, the restraining force of the material after flowing out from the opposing mandrel is significantly reduced, and the pressing force applied to the punch by the first drive device is significantly reduced. Can be reduced.

Thus, a rod-shaped material having various cross-sectional shapes is subjected to one heat by hot forging and one blow process, and is free from defects such as flesh and cracks on the surface and inside and is non-axial. A preform is obtained which has a material volume directionality and distribution adapted to a symmetrical product shape and has a substantially rational metal flow for the subsequent steps. Then, in the post process, the work of molding the preform of the final shape is
It can be handled as a simple axisymmetric shape, and can be completed in one heat in hot forging, and a product of good quality can be obtained.

Further, during molding, the opposing mandrel is longitudinally driven by the second driving device to control the distance between the opposing mandrel and the upper die to adjust the thickness of the lateral extrusion. The volume distribution in the direction can be changed,
This makes it possible to provide a material volume distribution adapted to a non-axisymmetric product shape. Furthermore, if the lower die is closely attached to the peripheral edge of the upper die to define a cavity between the upper die and the upper die, the material is substantially filled in the lateral direction of the cavity, and molding similar to closed forging is performed. In addition, the surfaces defining the cavities of the upper mold and the lower mold lightly support the material diffusing into the cavity from above and below to prevent the material from being deformed due to warpage or sag.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 show one embodiment of an apparatus used for carrying out the method of the present invention. In FIG. 1, reference numeral 15 indicates a gate-shaped frame, and an upper mold 1 which can be vertically driven by a plurality of cylinder devices 7 as a third driving device is provided on an upper portion of the frame 15. And the lower mold 2 is arranged at the lower part of the frame 15, and the peripheral edge of the upper mold 1 is in close contact with the lower mold 2 and has a deformed cross section other than a circular shape, that is, non-axisymmetric (for this embodiment). Defines a cavity 3 forming a triangle. An opposed mandrel 5 is fitted in the lower mold 2.

Further, a punch 4 which can be vertically driven by a cylinder device 8 which is a first drive device is arranged in the upper center of the frame 15, and the punch 4 which is driven downward by the cylinder device 8 is arranged above. It is fitted into a through hole 1a formed in the center of the mold 1. The lower corner portion of the through hole 1a of the upper die 1 forms a smooth surface by the chamfered portion 1b. 6 is a material to be preformed, and has a rod shape with various cross-sectional shapes. The material 6 is a non-ferrous metal, especially aluminum. The upper die 1 and the punch 4 can be raised and returned by a return cylinder device (not shown) to open the die.

On the other hand, the opposed mandrel 5 which can be vertically moved to a predetermined height position by the cylinder device 10 which is the second drive device at the lower center of the frame 15 is the cylinder device 10.
Is driven to move up and down, and slides through the through hole 2a formed in the central portion of the lower mold 2. Through hole 1 for punch 4 and upper die 1
The facing mandrel 5 has a larger surface than a.

Then, the cavity 3 of the opposed mandrel 5
A guide portion 5b for guiding the flow of the material 6 compressed in the central axis direction by the punch 4 and flowing in the lateral direction in a predetermined direction is formed on the material contact surface 5a that defines the. This guide 5
b has a function of adjusting the frictional force acting on the material 6 to be compressed and promoting the flow of the material 6 toward the deep part of the cavity 3. Specifically, as shown in FIG. Is formed by a groove extending toward each of the vertices 3a, 3b, 3c, which is the deep portion of the above, or an inclined portion shown in FIG.

Next, a method of performing preforming using the preforming apparatus having such a structure will be described. First, Fig. 1
As shown in FIG. 2, the upper mold 1 is driven downward by the cylinder device 7 to bring the molds 1 and 2 into close contact with each other to define the cavity 3.
Further, the heated columnar material 6 is put into the through hole 1 a of the upper mold 1. Further, the opposed mandrel 5 is a cylinder device 10
Is driven to slightly project into the cavity 3 from the lower mold 2 to hold the position.

From this state, as shown in FIG. 3, the punch 4 is lowered by the cylinder device 8 to move the through hole 1 of the upper mold 1.
The material 6 fitted in a is set up between the punch 4 and the opposing mandrel 5. When the punch 4 is further lowered to compress the material 6, the material is pushed laterally from the space formed by the opposing mandrel 5 and the upper mold 1 and diffused into the cavity 3.

At this time, the material contact surface 5 of the opposing mandrel 5
A guide portion 5b formed of a groove or an inclined portion for guiding the flow of the raw material 6 is formed in a, and the raw material 6 receives resistance to the flow toward each side of the triangular cavity 3, and thus is shown in FIG. As described above, the selected shunts extend toward the respective vertices 3a, 3b, 3c. The material 6 coming out from the material contact surface 5a of the facing mandrel 5 is lightly contacted with the upper mold 1 and the lower mold 2 after being pushed out in the lateral direction because the facing mandrel 5 slightly projects into the cavity 3. However, the frictional resistance is reduced and it flows out freely. The surfaces of the upper mold 1 and the lower mold 2 that define the cavities 3 support the material 6 that diffuses in the cavities 3 from above and below, and prevent the material 6 from being deformed due to warpage or sag.

Further, the punch 4 is lowered to compress the material 6, and the material 6 is almost filled in the lateral direction of the cavity 3 as shown in FIGS. Then, by adjusting the shape of the groove or the inclined portion of the guide portion 5b of the opposing mandrel 5,
Each side of the triangular cavity 3 and each vertex 3a, 3b,
It is possible to cause the material 6 to flow onto the 3c almost at the same time. In this way, the flow toward each side of the triangular cavity 3 is suppressed and freely flows out in the lateral direction, so that the restraining force between the upper mold 1 and the lower mold 2 is significantly reduced. Therefore, the pressing force which is the forming load applied to the punch 4 by the cylinder device 8 may be relatively small. Also, after molding,
If the upper die 1 and the punch 4 are pulled up by a return cylinder device (not shown) and separated from the lower die 2, the molded product can be taken out of the die.

Thus, the product shape is non-axisymmetric and free from defects such as surface defects and cracks on the surface and inside by one heat and one blowing process from the cylindrical material 6 by hot forging. Has a material volume orientation and distribution adapted to
A preform having a substantially rational metal flow is obtained in the post process. Therefore, the work of forming the final shape of the forged product in the post-process can be handled as a simple axisymmetric shape, and can be completed in one heat in the hot forging, and a product of good quality can be obtained. Obtainable. In the above description, since the opposing mandrel 5 is not moved up and down by the cylinder device 10, it is sufficient to form the opposing mandrel 5 integrally with the lower mold 2.

FIG. 7 and FIG. 8 show another structural example, in which the distance between the opposing mandrel 5 and the upper die 1 is controlled during preforming to adjust the thickness of the lateral extrusion, and the volume in the extrusion direction is adjusted. The distribution is changed. That is, if the opposing mandrel 5 is driven upward by the cylinder device 10 during the forming of the preformed product and the interval formed between the opposing mandrel 5 and the upper die 1 is appropriately reduced, the interval is changed laterally. The material 6 to be extruded has a reduced thickness thereafter, which makes it possible to provide a material volume distribution adapted to a non-axisymmetric product shape.

In the above embodiment, the case of obtaining a preform having a triangular cross section has been described, but as shown in FIG. 11, the guide portion 5b of the material contact surface 5a, as shown in FIG. It is needless to say that the material contact surface 5a of the opposed mandrel 5 can be widely applied to a non-axisymmetric preform by adjusting the planar shape of the material contact surface 5a itself.

[0022]

As can be understood from the above description,
According to the preforming method of a die forged product and the apparatus thereof according to the present invention, it becomes possible to shorten the preforming step while lowering the forging pressure for a product having a deformed shape and a high degree of non-axial symmetry, As a result, the productivity of the entire forging process can be improved. Further, since a good preform shape can be obtained for the final product, the material yield of the product can be improved. In addition, unlike conventional closed forging, molding is performed while controlling the flow direction of the material, so the required molding load is low, so it can be realized with a vertical drive device with a small capacity, and capital investment can be kept low. You can Such effects, especially in the metal or its alloy having excellent hot fluidity such as aluminum and aluminum alloy,
It can be obtained well.

[Brief description of drawings]

FIG. 1 is a front view showing a partial cross-section of a die forging preforming apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a lower mold and an opposing mandrel.

FIG. 3 is an explanatory view of the same operation.

FIG. 4 is a diagram showing the flow of materials in the same manner.

FIG. 5 is an explanatory view of the same operation.

FIG. 6 is a diagram showing the flow of materials in the same manner.

FIG. 7 is an explanatory view of the same operation.

FIG. 8 is a diagram showing the flow of materials in the same manner.

FIG. 9 is a plan view showing another structural example of the material contact surface of the facing mandrel in the same manner.

FIG. 10 is a sectional view showing another structural example of the material contact surface of the facing mandrel in the same manner.

FIG. 11 is a plan view showing another structural example of the material contact surface of the facing mandrel in the same manner.

[Explanation of symbols]

1: upper mold, 1a: through hole, 2: lower mold, 2a: through hole,
3: Cavities 3a, 3b, 3c: Apex, 4: Punch, 5: Opposing mandrel, 5a: Material contact surface, 5b: Guide part, 6: Material, 7: Cylinder device (third drive device),
8: Cylinder device (first drive device), 10: Cylinder device (second drive device), 15: Frame.

Claims (5)

[Claims] 1. An upper mold having a through hole into which rod-shaped materials having various cross-sectional shapes are inserted, and a predetermined gap is formed between the upper mold and the upper mold so as to face each other. Also has a facing mandrel having a large material contact surface, and a punch that is inserted into the through hole of the upper mold from above the material and is driven in the longitudinal direction by the first driving device. Using a preforming device in which a guide portion consisting of a groove, an inclined portion, etc. for guiding the flow of the material compressed by the punch is formed on the material contact surface, the material to be inserted from the through hole of the upper die is , Compressing between the punch and the material contact surface of the opposing mandrel, and guiding the flow by the guide portion of the material contact surface to allow the material to flow laterally from between the upper die and the material contact surface of the opposing mandrel. , A preform for die forgings, which is characterized by forming a deformed preform. Preparation method. 2. A facing mandrel having a guide portion formed on a material contact surface is provided with a second drive device for driving in the vertical direction, and the facing mandrel is moved in the vertical direction when forming a preform to change the wall thickness. The preforming method for a die forged product according to claim 1, wherein 3. An upper die having a through hole into which rod-shaped raw materials having various cross-sectional shapes are inserted, and a material which is compressed at opposing material contact surfaces with a predetermined gap formed between the upper die and the upper die. Forming a guide portion composed of a groove, an inclined portion, etc. for guiding the flow of the material, and a facing mandrel which is larger than the through hole of the upper mold facing the material contact surface, and the through hole of the material of the upper mold. A preforming device for a die forged product, comprising a punch inserted from above and vertically driven by a first drive device. 4. The preforming device for a die forged product according to claim 3, wherein the opposed mandrel is vertically driven by a second driving device. 5. The opposed mandrel is inserted into a through hole of a lower mold which is in close contact with a peripheral portion of the upper mold and defines a cavity between the opposed mandrel and the upper mold. Preformer for die forgings.