Combined die and using method thereof

Abstract

The invention relates to the technical field of forging and pressing, in particular to a combined die and a using method thereof. Comprising a male die and a female die, the male die comprises a base and a boss, the side face of the boss comprises a first cylindrical face, a second cylindrical face and a first forming face which are coaxially arranged, and the first cylindrical face, the second cylindrical face and the first forming face are sequentially connected; a forming cavity used in cooperation with the boss is formed in the upper surface of the female die, the side face of the forming cavity comprises a third forming face and a fourth forming face which are sequentially connected, and the third forming face and the bottom face of the forming cavity are in smooth transition. The first cylindrical surface and the second cylindrical surface are arranged on the boss, the diameter of the first cylindrical surface is smaller than that of the second cylindrical surface, the third forming surface and the fourth forming surface are arranged in the forming cavity, and in the forging forming process, the cylinder wall is formed under the action of the second cylindrical surface and the fourth forming surface; the inner side face of the cylinder wall only makes contact with the second cylindrical face and does not make contact with the first cylindrical face, and contact between the forge piece and a die is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of forging, and in particular to a combined die and a method for using the same. Background Art

[0002] Thin-walled deep-cavity parts are widely used in the field of aerospace engines, and they have typical hollow structural characteristics. Generally, such parts are formed by extrusion and machining. The heated blank is placed in the die, and the punch is used to press down to form a cylindrical forging. After the forging is formed, the burrs, skin and other excess parts are removed by machining to finally form the parts. However, this extrusion molding method causes violent metal flow, which causes severe wear on the mold cavity. After extrusion molding, the forging fits the mold over a large area, resulting in huge demoulding force. When conventional ejection and demoulding methods act on such thin-walled forgings, the huge ejection force can easily cause the forgings to deform, affecting the external dimensions of the forgings. In addition, in order to ensure the smooth molding and demoulding of the forgings, the forgings are usually designed with a large draft angle and a large margin, resulting in high material costs.

[0003] A thin-walled deep cavity part such as Figure 1 As shown, Figure 2 is a schematic diagram of a forging formed by the first die, and the forging obtained is as follows Figure 3 As shown, the contact between the forging and the die is as follows Figure 2 As shown. From the contact situation, it can be seen that after the forging is extruded, the inner surface of the forging is in full contact with the outer surface of the punch, and the outer surface of the forging is in full contact with the inner surface of the die. During demolding, due to the large-area contact between the forging and the die, the required demolding force is huge, and it is easy to cause deformation of the forging and poor surface quality. At the same time, the large-area and long-term contact between the thin-walled forging and the die can easily lead to a large temperature drop in the forging body. After the forging shrinks, the risk of die sticking is further increased. In addition, due to the large size of the thin-walled deep-cavity parts, the large draft angle designed for the forging further increases the volume of the forging and reduces the material utilization rate.

[0004] If the die is not designed with a draft angle and a straight wall design is used directly, the material utilization rate can be improved. The contact between the forging and the second die is as follows: Figure 4 As shown, the obtained forging is Figure 5 After extrusion molding, it can be seen that although the lack of draft angle design for forgings can improve material utilization, it makes it more difficult to demold the forgings due to the lack of draft angle design, and does not solve the risk of easy deformation and die sticking during demolding of forgings. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a combined die and a method for using the same, so as to reduce the contact area between the forging and the die during the forming process of the barrel forging and better realize the demoulding of the forging.

[0006] The technical solution adopted by the present invention to solve its technical problem is a combined mold, including a punch and a die, the punch including a base and a boss, the side surface of the boss including a first cylindrical surface, a second cylindrical surface and an annular first molding surface which are coaxially arranged, the first cylindrical surface, the second cylindrical surface and the annular first molding surface are connected in sequence, the diameter of the first cylindrical surface is smaller than the diameter of the second cylindrical surface, the upper end diameter of the first molding surface is larger than the lower end diameter, and the upper end diameter of the first molding surface is not larger than the diameter of the second cylindrical surface; the lower surface of the boss is connected to the first molding surface through the second molding surface, the upper end diameter of the second molding surface is larger than the lower end diameter, and the upper end diameter of the second molding surface is not larger than the lower end diameter of the first molding surface; the angle between the second molding surface and the horizontal plane is 3-5°, and the angle between the first molding surface and the horizontal plane is 45-60°;

[0007] The upper surface of the die is provided with a molding cavity used in conjunction with the boss, and the side of the molding cavity includes a third molding surface and a fourth molding surface connected in sequence, the third molding surface smoothly transitions with the bottom surface of the molding cavity, the third molding surface forms a first angle with the horizontal plane, and the fourth molding surface forms a second angle with the horizontal plane, the second angle is 91 to 93°, and the first angle is 94 to 96°.

[0008] Furthermore, the first cylindrical surface, the second cylindrical surface and the first annular forming surface are all transitioned by arcs.

[0009] A method for using a combined mold, using a combined mold, comprising the following steps:

[0010] S1, installing the punch on the upper die base of the hydraulic forging machine, installing the die on the lower die base of the hydraulic forging machine, placing the blank in a heating furnace for heating, and placing the blank in the forming cavity of the die after the blank reaches the forging temperature;

[0011] S2: The hydraulic forging machine drives the punch to move downward until the lower surface of the boss contacts the upper surface of the blank. At this time, the second cylindrical surface and the fourth forming surface are opposite to each other, and the punch continues to be driven downward. During the downward movement of the punch, the blank gradually deforms and fills the bottom of the die.

[0012] S3: Continue to drive the punch downward, and the metal in the blank will continue to flow along the first forming surface to between the second cylindrical surface and the fourth forming surface, and a cylindrical metal wall will be formed under the action of the second cylindrical surface and the fourth forming surface. As the punch continues to move downward, the metal wall gradually rises and finally forms a cylindrical wall.

[0013] Furthermore, the hydraulic rapid forging machine drives the punch to move downward at a speed of 20 to 30 mm / s.

[0014] The beneficial effects of the present invention are as follows: by arranging a first cylindrical surface and a second cylindrical surface on the boss, the diameter of the first cylindrical surface is smaller than the diameter of the second cylindrical surface, and arranging a third molding surface and a fourth molding surface in the molding cavity, a first angle is formed between the third molding surface and the bottom surface of the molding cavity, and a second angle is formed between the fourth molding surface and the bottom surface of the molding cavity. During the forging forming process, a cylinder wall is formed under the action of the second cylindrical surface and the fourth molding surface, and the inner side surface of the cylinder wall only contacts the second cylindrical surface but not the first cylindrical surface. At the same time, in the initial stage of extrusion forming the cylinder wall, the initially formed cylinder wall is tightly attached to the fourth molding surface, but as the punch continues to move downward, the cylinder wall will gradually rise. At this time, the thickness of the initially formed cylinder wall is smaller than the vertical distance from the fourth molding surface to the second cylindrical surface. Therefore, only a part of the cylinder wall being formed contacts the fourth molding surface, and the rest of the cylinder wall is separated from the fourth molding surface, thereby reducing the contact between the forging and the mold, and reducing the temperature drop of the forging and the required demolding force. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of existing parts;

[0016] Figure 2 is a schematic diagram of the first type of die forming the first type of forging;

[0017] Figure 3 It is a schematic diagram of the first type of forging;

[0018] Figure 4 is a schematic diagram of the second type of forging formed by the second die;

[0019] Figure 5 is a schematic diagram of the second type of forging;

[0020] Figure 6 It is a schematic diagram of the mold of the present invention;

[0021] Figure 7 Is adopted Figure 6 Schematic diagram of forging formed by die;

[0022] Figure 8-Figure 12 Is adopted Figure 6 Mold Forming Figure 7 Flowchart of forgings.

[0023] Figure numerals: 1-punch; 2-base; 3-boss; 4-first cylindrical surface; 5-second cylindrical surface; 6-first molding surface; 7-die; 8-molding cavity; 9-third molding surface; 10-fourth molding surface; 11-second molding surface. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0025] like Figure 6-Figure 7 As shown, the present invention is a combined mold, including a punch 1 and a die 7, the punch 1 includes a base 2 and a boss 3, the side of the boss 3 includes a first cylindrical surface 4, a second cylindrical surface 5 and an annular first molding surface 6 arranged coaxially, the first cylindrical surface 4, the second cylindrical surface 5 and the annular first molding surface 6 are connected in sequence, the diameter of the first cylindrical surface 4 is smaller than the diameter of the second cylindrical surface 5, the upper end diameter of the first molding surface 6 is larger than the lower end diameter, and the upper end diameter of the first molding surface 6 is not larger than the diameter of the second cylindrical surface 5; the lower surface of the boss 3 and the first molding surface 6 are connected by the second molding surface 6. The upper end diameter of the second molding surface 11 is larger than the lower end diameter, and the upper end diameter of the second molding surface 11 is not larger than the lower end diameter of the first molding surface 6; the upper surface of the die 7 is provided with a molding cavity 8 used in conjunction with the boss 3, and the side surface of the molding cavity 8 includes a third molding surface 9 and a fourth molding surface 10 connected in sequence, the third molding surface 9 and the bottom surface of the molding cavity 8 have a smooth transition, the third molding surface 9 forms a first angle with the horizontal plane, the fourth molding surface 10 forms a second angle with the horizontal plane, the second angle is 91-93°, and the first angle is 94-96°.

[0026] Among them, the base 2 and the boss 3 are integrally formed, the boss 3 is used to form the inner wall of the forging, the first cylindrical surface 4, the second cylindrical surface 5 and the annular first forming surface 6 are connected in sequence, the height of the second cylindrical surface 5 is 10-20% of the height of the boss 3, the height of the first forming surface 6 is also 10-20% of the height of the boss 3, the second cylindrical surface 5 is used to form a cylindrical metal wall with the fourth forming surface 10, the diameter of the first cylindrical surface 4 is smaller than the diameter of the second cylindrical surface 5, so that when the metal wall is formed, the inner side of the metal wall does not contact the first cylindrical surface 4; the first function of the first forming surface 6 is to guide the flow of the metal, and at the same time, because the upper end diameter of the first forming surface 6 is larger than the lower end diameter, and the upper end diameter of the first forming surface 6 is not larger than the diameter of the second cylindrical surface 5, the second forming surface 11 is in an inclined state, and the second function of the second forming surface 11 is to facilitate the separation of the forging after forming from the second forming surface 11; the forming cavity 8 is used to form the outer wall of the forging, and the minimum diameter of the forming cavity 8 needs to be larger than the maximum diameter of the boss 3, so that the boss 3 can be placed in the forming cavity 8, the bottom surface of the molding cavity 8 is a plane and parallel to the horizontal plane, the third molding surface 9 forms a first angle with the horizontal plane, and the fourth molding surface 10 forms a second angle with the horizontal plane, the second angle is 91-93°, and the first angle is 94-96°. In this way, in the initial stage of extrusion molding of the metal wall, the initially molded metal wall is in close contact with the fourth molding surface 10, but as the punch continues to move downward, the metal wall will gradually rise. At this time, the thickness of the initially formed metal wall is less than the vertical distance from the fourth molding surface 10 to the second cylindrical surface 5, so only part of the metal wall being molded is in contact with the fourth molding surface 10, and the rest of the metal wall is separated from the fourth molding surface 10. At the same time, the closer to the lower end of the fourth molding surface 10, the smaller the vertical distance from the fourth molding surface 10 to the second cylindrical surface 5, the smaller the thickness of the molded metal wall, and the less material used; the first angle formed by the third molding surface 9 and the horizontal plane is greater than the second angle formed by the fourth molding surface 10 and the horizontal plane, so that the slope of the third molding surface 9 is larger, which can further reduce the amount of material used.

[0027] To ensure smooth metal flow, see Figure 6 The first cylindrical surface 4, the second cylindrical surface 5 and the annular first forming surface 6 are all transitioned by arcs.

[0028] In order to facilitate the forming of forgings, further, the angle between the second forming surface 11 and the horizontal plane is 3 to 5 degrees, which is conducive to the flow of metal to the first forming surface 6 during extrusion; in order to enable the metal to flow upward better during extrusion and reduce the wear of the punch, the angle between the first forming surface 6 and the horizontal plane is 45 to 60 degrees.

[0029] A method for using a combined mold, using a combined mold, including the following steps, see Figure 8-Figure 12 ,

[0030] S1, installing the punch 1 on the upper die base of the hydraulic fast forging machine, installing the die 7 on the lower die base of the hydraulic fast forging machine, placing the blank in a heating furnace for heating, and placing the blank in the forming cavity 8 of the die 7 after the blank reaches the forging temperature;

[0031] S2: The hydraulic forging machine drives the punch 1 to move downward until the lower surface of the boss 3 contacts the upper surface of the blank. At this time, the second cylindrical surface 5 and the fourth forming surface 10 are opposite to each other, and the punch 1 is driven to move downward. During the downward movement of the punch 1, the blank gradually deforms and fills the bottom of the die 7.

[0032] S3: Continue to drive the punch 1 downward, and the metal in the blank will continue to flow along the first forming surface 6 to between the second cylindrical surface 5 and the fourth forming surface 10, and a cylindrical metal wall will be formed under the action of the second cylindrical surface 5 and the fourth forming surface 10. As the punch 1 continues to move downward, the metal wall gradually rises and finally forms a cylindrical wall.

[0033] Furthermore, the hydraulic rapid forging machine drives the punch 1 to move downward at a speed of 20 to 30 mm / s.

[0034] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A combined mold, comprising a male mold (1) and a female mold (7), characterized in that: The punch (1) comprises a base (2) and a boss (3); the side surface of the boss (3) comprises a first cylindrical surface (4), a second cylindrical surface (5) and an annular first molding surface (6) which are coaxially arranged; the first cylindrical surface (4), the second cylindrical surface (5) and the annular first molding surface (6) are connected in sequence; the diameter of the first cylindrical surface (4) is smaller than the diameter of the second cylindrical surface (5); the upper end diameter of the first molding surface (6) is larger than the lower end diameter; and the upper end diameter of the first molding surface (6) is not larger than the diameter of the second cylindrical surface (5); the lower surface of the boss (3) is connected to the first molding surface (6) via a second molding surface (11); the upper end diameter of the second molding surface (11) is larger than the lower end diameter; and the upper end diameter of the second molding surface (11) is not larger than the lower end diameter of the first molding surface (6); the included angle between the second molding surface (11) and the horizontal plane is 3 to 5 degrees; and the included angle between the first molding surface (6) and the horizontal plane is 45 to 60 degrees; The upper surface of the die (7) is provided with a molding cavity (8) for use with the boss (3); the side surface of the molding cavity (8) includes a third molding surface (9) and a fourth molding surface (10) connected in sequence; the third molding surface (9) and the bottom surface of the molding cavity (8) form a smooth transition; the third molding surface (9) forms a first angle with a horizontal plane; the fourth molding surface (10) forms a second angle with the horizontal plane; the second angle is 91 to 93°; and the first angle is 94 to 96°.

2. A combined mold according to claim 1, characterized in that: The first cylindrical surface (4), the second cylindrical surface (5) and the annular first molding surface (6) are all transitioned through circular arcs.

3. A method for using a combined mold, using a combined mold as claimed in any one of claims 1 to 2, characterized in that: The following steps are included: S1, installing the punch (1) on the upper die base of the hydraulic fast forging machine, installing the die (7) on the lower die base of the hydraulic fast forging machine, placing the blank in a heating furnace for heating, and placing the blank in the forming cavity (8) of the die (7) after the blank reaches the forging temperature; S2: The hydraulic forging machine drives the punch (1) to move downward until the lower surface of the boss (3) contacts the upper surface of the blank. At this time, the second cylindrical surface (5) and the fourth forming surface (10) are opposite to each other, and the punch (1) continues to be driven downward. During the downward movement of the punch (1), the blank gradually deforms and fills the bottom of the die (7); S3: The punch (1) is continuously driven downward, and the metal in the blank continues to flow along the first forming surface (6) to between the second cylindrical surface (5) and the fourth forming surface (10), and a cylindrical metal wall is formed under the action of the second cylindrical surface (5) and the fourth forming surface (10). As the punch (1) continues to move downward, the metal wall gradually rises and finally forms a cylindrical wall.

4. The method for using a combined mold according to claim 3, characterized in that: The hydraulic fast forging machine drives the punch (1) to move downward at a speed of 20 to 30 mm / s.

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