A die for a forging having a frusto-conical edge

Abstract

The application provides a die for a forging part with a circular table at the edge, and relates to the field of forging technology. The die for the forging part with the circular table at the edge has a cavity, which comprises a forging body part, a bridge part and a bin part. The root of the forging body part is provided with a circular table cavity for shaping a circular table of the forging part. The bridge part comprises a first section and a second section corresponding to the position of the circular table cavity. The second section has a structure with the height gradually increasing from both ends to the middle. The application can reduce the manufacturing cost of the die.

Description

Technical Field

[0001] This invention relates to the field of forging technology, and more specifically to a forging die. Background Technology

[0002] With the development of aircraft, in order to fly higher and faster and achieve better fuel economy, the main load-bearing structural components are increasingly being manufactured using non-ferrous alloys such as aluminum alloys and titanium alloys, which can reduce weight. However, some parts with extremely high strength requirements still need to be made of high-strength steel. Unlike steel used in other industries such as automobiles, high-strength steel has characteristics such as high chemical composition, high deformation resistance, and difficult metal flow, resulting in greater wear on the molds. Taking the second-generation high-strength steel 30CrMnSiNi2A forgings for aircraft as an example, the forging temperature of this type of forging is generally in the range of 800-1150℃. The die forging process is generally carried out on hammer forging equipment. In order to better remove the oxide scale on the surface of the forging, a mixture of wet sawdust and coarse salt is added during the forging process. When it comes into contact with the high-temperature forging, it generates explosive gas, which impacts the oxide scale on the surface of the forging, thereby improving the surface quality of the forging. The die forging process requires multiple forging operations. During the forging process, the die is subjected to multiple alternating load impacts. For forgings with frustums at the edge, the frustum cavity at the root of the die is prone to fatigue failure and cracks, which can lead to the scrapping of the die.

[0003] Conventional methods for addressing mold fatigue failure include special heat treatment to improve the mold's fatigue resistance or using materials with higher fatigue resistance as mold materials, but these methods result in higher mold costs.

[0004] Forging die 1 includes an upper die and a lower die, which cooperate to form cavity 1, such as Figure 1 The mold cavity 1 shown consists of three parts: the forging body 11, the bridge 12, and the storage compartment 13. The intersection of the forging and the parting surfaces of the upper and lower molds forms a contour diagram, which is the maximum contour of the forging in its top view. The bridge 12 and storage compartment 13 are connected to the forging body 11 and perpendicular to the parting surface. Rotating around this contour diagram completes the design of the mold cavity 1. The bridge 12's function is to prevent metal from flowing out of the mold cavity, promoting forging formation. The height H of the bridge 12 is usually designed according to the size of the mold cavity; generally, the height of the bridges at various locations within the same mold is consistent. The storage compartment 13 is for storing excess metal. For the root frustum cavity, where molds are highly susceptible to fatigue failure and cracking, it was found that changing the structure of the bridge at this location not only affects the resistance to metal flow during forging but also further influences the stress state of the mold during the forging process, thereby improving the mold's fatigue strength and being the most economical approach. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a forging mold with a frustum on the edge, so as to change the stress state at the frustum cavity at the root of the mold and improve the fatigue strength of the mold.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a forging mold with a frustum on the edge, the cavity of the mold includes a forging body, a bridge and a cavity, the root of the forging body is provided with a frustum cavity for forming the forging frustum, the bridge includes a first section and a second section corresponding to the position of the frustum cavity, the second section adopts a structure in which the height gradually increases from both ends to the middle.

[0007] Furthermore, the top surface of the second segment has a structure that gradually concaves upwards from both ends to the middle, and the bottom surface of the second segment has a structure that gradually concaves downwards from both ends to the middle.

[0008] Furthermore, the top surface of the second segment is inclined from both ends toward the middle to form an upward concave structure, and the bottom surface of the second segment is inclined from both ends toward the middle to form a downward concave structure. The inclination of the top and bottom surfaces of the second segment is X, where X = [(0.3~0.8)L / H], and L is the distance between the two ends of the second segment, and H is the height of the first segment.

[0009] The beneficial effects of the present invention are as follows: After the bridge part, i.e. the second section, corresponding to the frustum cavity is set in the mold of the present invention to have a structure in which the height gradually increases from both ends to the middle, the metal outflow resistance at the frustum cavity position at the root of the mold is reduced, which can reduce the impact of alternating loads on the mold during the forging process, i.e. the stress state. Therefore, without the need for special heat treatment of the mold or the use of materials with higher fatigue strength as mold materials, the fatigue strength of the mold can be improved, and the mold manufacturing cost can be reduced. Attached Figure Description

[0010] Figure 1 This is a structural diagram of the mold cavity;

[0011] Figure 2 yes Figure 1 Sectional view along AA;

[0012] Figure 3 yes Figure 1 Sectional view along BB;

[0013] Figure 4 yes Figure 3 Enlarged view of point C;

[0014] Figures 5 to 8 This is a stress analysis diagram of the mold;

[0015] The figure shows: forging body 11, bridge 12, chamber 13, frustum cavity 111, first section 121, and second section 122. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] like Figure 1 , Figure 2 As shown, a forging mold with a frustum at its edge according to the present invention includes a forging body portion 11, a bridge portion 12, and a cavity portion 13. The root of the forging body portion 11 is provided with a frustum cavity 111 for forming the frustum of the forging. The bridge portion 12 includes a first segment 121 and a second segment 122 corresponding to the position of the frustum cavity 111. See also... Figure 3 , Figure 4 The second segment 122 adopts a structure in which the height gradually increases from both ends to the middle.

[0018] The mold of the present invention has a structure in which the bridge part, i.e. the second section 122, corresponding to the frustum cavity 111, is configured such that the height gradually increases from both ends to the middle. This reduces the resistance to metal outflow at the frustum cavity at the root of the mold, thereby reducing the impact of alternating loads on the mold during the forging process, i.e. the stress state, and thus improving the fatigue strength of the mold.

[0019] Specifically, the second segment 122 can adopt a concave bottom and / or concave top surface to achieve a structure in which the height gradually increases from both ends to the middle. Preferably, as... Figure 4 As shown, the top surface of the second segment 122 has a structure that gradually concaves upwards from both ends to the middle, and the bottom surface of the second segment 122 has a structure that gradually concaves downwards from both ends to the middle, thus achieving a structure that gradually increases in size from both ends to the middle. In this way, the upper and lower molds of the mold are subjected to more uniform force.

[0020] like Figure 4 As shown, in one embodiment of the present invention, the top surface of the second segment 122 is inclined from both ends toward the middle to form an upwardly concave structure, and the bottom surface of the second segment 122 is inclined from both ends toward the middle to form a downwardly concave structure. The inclination of both the top and bottom surfaces of the second segment 122 is X, where X = [(0.3~0.8)L / H], and L is the distance between the two ends of the second segment, and H is the height of the first segment 121. Through simulation, the above structure has the best effect on improving the stress at the root frustum cavity of the mold, the best effect on improving the fatigue strength of the mold, and does not waste a lot of forging material. It is most beneficial to the forming of the forging and does not affect the material filling into the frustum cavity 111.

[0021] Example 1

[0022] The forging is an aircraft rod head forging, made of 30CrMnSiNi2A material. Based on the structure of the forging body (forging body 11), the bridge portion of the forging adopts the same structure, with a bridge width D = 20mm and a height H = 8mm. The stress analysis of the die is as follows... Figure 5 .

[0023] Example 2

[0024] The forging is an aircraft rod head forging, made of 30CrMnSiNi2A material. Based on the structure of the forging (body 11), the first section 122 has a bridge width D = 20mm and a height H = 8mm. The second section 122's bridge adopts a top surface that slopes upwards from both ends to the middle to form an upward concave structure, and a bottom surface that slopes downwards from both ends to the middle to form a downward concave structure, thus achieving a gradual increase in height from both ends to the middle. The slope of both the top and bottom surfaces of the second section is X, where X = 0.3L / H = 2.3°. The stress analysis of the mold is as follows... Figure 6 ,compared to Figure 5 The maximum stress value of the mold was reduced by 265 MPa, and the forming of the forging frustum was good, meeting the requirements.

[0025] Example 3

[0026] The forging is an aircraft rod head forging, made of 30CrMnSiNi2A material. Based on the structure of the forging (body 11), the first section 122 has a bridge width D = 20mm and a height H = 8mm. The second section 122's bridge adopts a top surface that slopes upwards from both ends to the middle to form an upward concave structure, and a bottom surface that slopes downwards from both ends to the middle to form a downward concave structure, thus achieving a gradual increase in height from both ends to the middle. The slope of both the top and bottom surfaces of the second section is X, where X = 0.6L / H = 4.5°. The stress analysis of the mold is as follows... Figure 7 ,compared to Figure 5 The maximum stress value of the mold was reduced by 420MPa, and the forming of the forging frustum was good, meeting the requirements.

[0027] Example 4

[0028] The forging is an aircraft rod head forging, made of 30CrMnSiNi2A material. Based on the structure of the forging (body 11), the first section 122 has a bridge width D = 20mm and a height H = 8mm. The second section 122's bridge features a top surface that slopes upwards from both ends to the middle to form an upward concave structure, and a bottom surface that slopes downwards from both ends to the middle to form a downward concave structure, thus gradually increasing the height from both ends to the middle. The slope of both the top and bottom surfaces of the second section is X, where X = 0.8L / H = 6°. The stress analysis of the mold is as follows... Figure 8 ,compared to Figure 5 The maximum stress value of the mold was reduced by 457 MPa, and the forming of the forging frustum was good, meeting the requirements.

Claims

1. A forging mold with a frustum at its edge, the mold cavity comprising a forging body portion (11), a bridge portion (12), and a storage portion (13), wherein the root of the forging body portion (11) is provided with a frustum cavity (111) for forming a frustum of the forging, and the bridge portion (12) comprises a first segment (121) and a second segment (122) corresponding to the position of the frustum cavity (111), characterized in that: The second segment (122) adopts a structure in which the height gradually increases from both ends to the middle; The top surface of the second segment (122) is inclined from both ends toward the middle to form an upward concave structure, and the bottom surface of the second segment (122) is inclined from both ends toward the middle to form a downward concave structure. The inclination of the top and bottom surfaces of the second segment (122) is X, where X = [(0.3~0.8)L / H], and L is the distance between the two ends of the second segment, and H is the height of the first segment (121).

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