CN117483531B - Convex hull forming process for high-strength large-thickness material - Google Patents
Convex hull forming process for high-strength large-thickness material Download PDFInfo
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- CN117483531B CN117483531B CN202311823919.6A CN202311823919A CN117483531B CN 117483531 B CN117483531 B CN 117483531B CN 202311823919 A CN202311823919 A CN 202311823919A CN 117483531 B CN117483531 B CN 117483531B
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- 239000000463 material Substances 0.000 title claims abstract description 109
- 238000000034 method Methods 0.000 title claims abstract description 55
- 238000001125 extrusion Methods 0.000 claims abstract description 13
- 238000005336 cracking Methods 0.000 claims abstract description 10
- 238000004080 punching Methods 0.000 claims description 47
- 238000000465 moulding Methods 0.000 claims description 7
- 238000003825 pressing Methods 0.000 claims description 5
- 230000006835 compression Effects 0.000 description 6
- 238000007906 compression Methods 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000013589 supplement Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Abstract
The invention provides a convex hull forming process for high-strength and large-thickness materials, which adopts an extrusion process to form a convex hull by one-step forming. The convex hull forming process for the high-strength large-thickness material provided by the invention can be used for avoiding the problems of cracking, appearance wrinkling and influence on the effective height caused by overlarge internal R angle.
Description
Technical Field
The invention belongs to the technical field of forming processes, and particularly relates to a convex hull forming process for a high-strength large-thickness material.
Background
The high-strength steel is a steel material having a yield strength of 355MPa or more. The thickness of 3mm or more is called a large thickness. At present, the convex hull forming of the high-strength large-thickness steel plate mainly adopts a multi-step stretching process, is generally divided into three to five steps according to different stretching forming heights and stretching diameters, is formed from the first step to the last step based on the final forming heights and diameters, gradually reduces the stretching diameters and gradually increases the stretching heights according to the stretching ratio of 60% -85%, and is finally formed. However, since the high-strength steel material has poor fluidity, the material may be hardened during a multi-step drawing process, resulting in the generation of wrinkles, uneven bottoms, etc. during the multi-step drawing process. Meanwhile, in order to reduce cracking in the stretching process, the R angle at the bottom of the stretching needs to be increased as much as possible, so that the effective area of the stretching straight line section is reduced, namely the effective height of the convex hull is reduced.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the convex hull forming process for the high-strength large-thickness material is capable of avoiding the problems that cracking, appearance wrinkling and overlarge internal R angle affect the effective height.
In order to solve the technical problems, the embodiment of the invention provides a convex hull forming process for high-strength and large-thickness materials, which adopts an extrusion process to form a convex hull by one-step forming.
As a further improvement of the embodiment of the invention, the convex hull is formed by adopting an extrusion process for one-step molding, and the method specifically comprises the following steps:
Placing the material plate on a lower die stamping female die, and lowering an upper die stamping head to stamp the material plate, so that the material plate is extruded into the lower die stamping female die to form a convex hull with a preset height; and the upper die punch and the lower die stamping female die are matched.
As a further improvement of the embodiment of the invention, back pressure is provided for the material plate below the punching position of the material plate by the upper die punch in the process of punching the material plate downwards by the upper die punch.
As a further improvement of the embodiment of the present invention, the magnitude of the back pressure is set according to the formula (1):
F=5×10 6 ×s type (1)
Wherein F represents the back pressure, and S represents the preset bottom area of the convex hull.
As a further improvement of the embodiment of the invention, a push rod is arranged in the lower die stamping female die, and a driving piece is connected below the push rod; in the process of punching the material plate by the upper die punch, the ejector rod descends and always abuts against the material plate, and the driving piece provides back pressure for the material plate through the ejector rod.
As a further improvement of the embodiment of the invention, the upper die punch head is provided with steps with thick upper part and thin lower part.
As a further improvement of the embodiment of the invention, the upper die punch head comprises a first punching shaft and a second punching shaft, wherein the second punching shaft is arranged at the top end of the first punching shaft, the diameter of the second punching shaft is larger than that of the first punching shaft, and a step is formed at the joint of the first punching shaft and the second punching shaft.
As a further improvement of the embodiment of the invention, the upper die punch descends to punch the material plate, and if the height of the convex hull does not reach the preset height after the bottom of the second punching shaft reaches the upper surface of the material plate in the process of extruding the material plate into the lower die punching female die, the upper die punch descends continuously, and the second punching shaft extrudes part of the material in the thickness of the material plate into the lower die punching female die.
As a further improvement of the embodiment of the invention, the second pressing shaft presses the material plate downwards to a height not more than half the thickness of the material plate.
As a further improvement of the embodiment of the present invention, the diameter difference between the second punching shaft and the first punching shaft is 2 to 2.4mm.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
(1) According to the invention, an extrusion process is adopted, strong pressure is applied to the material plate, the material plate is extruded into the female die, the convex hull is formed by one-step molding, multi-step stretch molding is not needed, the conditions of cracking, wrinkling and poor flatness of the root of the convex hull caused by hardening of materials in the multi-step stretch process are avoided, and the R angle of the convex hull can be also not needed to be large, so that the effective height of the inside of the convex hull is ensured. The extrusion process adopts a single-step procedure, reduces procedure steps, improves production efficiency, and only needs to adopt a set of matched upper die punch and lower die punch female die, thereby reducing die manufacturing cost.
(2) In the process of punching the material plate downwards by the upper die punch, back pressure is provided for the material plate, so that material plate materials are slowly extruded into the lower die punching female die to slowly form a convex hull, and cracking of the materials due to rapid stretching is avoided. The back pressure is set according to the preset area of the bottom of the convex hull, the larger the preset area of the bottom of the convex hull is, the larger the back pressure is, and in the extrusion process, the bottom of the convex hull forms good flatness under the action of an upper die punch and a push rod with large back pressure. The ejector rod is arranged in the lower die stamping female die, the material plate is supported when the material plate is discharged, the upper die punch descends along with the upper die punch in the pressing process, back pressure is provided for the material plate, and the convex hull is pushed out of the lower die stamping female die after stamping forming.
(3) The upper die punch is provided with an upper-thick and lower-thin step structure, when the height of forming the convex hull by extruding at the lower part of the step of the upper die punch does not reach the preset height, part of materials in the thickness direction of the material plate are extruded into the lower die stamping die by the upper part of the step to form the convex hull, so that the effective height of the convex hull is increased, and meanwhile, the risk of cracking the side wall of the convex hull is reduced.
Drawings
FIG. 1 is a schematic diagram of working states of an upper die punch and a lower die punch die adopted in a convex hull forming process according to an embodiment of the present invention;
FIG. 2 is a one-step forming and decomposing schematic diagram of a convex hull forming process according to an embodiment of the present invention;
Fig. 3 is a schematic diagram of a convex hull structure formed by the convex hull forming process according to an embodiment of the present invention.
The drawings are as follows: the upper die punch 1, the material plate 2, the lower die punch concave die 3, the ejector rod 4 and the convex hull 5.
Detailed Description
The technical scheme of the invention is described in detail below with reference to the accompanying drawings.
The embodiment of the invention provides a convex hull forming process for high-strength and large-thickness materials, which adopts an extrusion process to form a convex hull by one-step forming. The method specifically comprises the following steps:
As shown in fig. 1, a material plate 2 is placed on a lower die stamping female die 3, an upper die stamping head 1 descends to stamp the material plate 2, and the material plate 2 is extruded into the lower die stamping female die 3 to form a convex hull with a preset size.
Wherein the material plate 2 is a steel plate, and the thickness of the material plate 2 is 2.5-5 mm, such as 2.5mm, 3mm, 3.6mm, 4.5mm, 5mm and the like; the tensile strength of the material plate 2 is 355 to 700MP, for example 355MP, 430MP, 520MP, 600MP, 680MP, 700MP, etc. The preset dimensions of the convex hull include a preset height, a preset inner diameter, and a preset outer diameter. The upper die punch 1 is matched with the lower die stamping die 3. The outer diameter of the upper die punch 1 is set according to the preset inner diameter of the convex hull, the inner diameter of the lower die stamping die 3 is set according to the preset outer diameter of the convex hull, and the descending height of the upper die punch 1 is set according to the preset height of the convex hull.
According to the embodiment of the invention, the convex hull is formed by adopting an extrusion process through one-step molding, so that the conditions of cracking, wrinkling and poor flatness caused by hardening of materials in the multi-step stretching process are avoided, and the R angle of the convex hull can be free from being large, thereby ensuring the effective height of the inside of the convex hull. In this embodiment, the convex hull R angle is R0.45-R0.55 mm, such as R0.45mm, R0.5mm, R0.55mm. The one-step molding only adopts a single-step procedure, reduces procedure steps, improves production efficiency, and only adopts a set of matched upper die punch and lower die punch female die, thereby reducing molding cost.
As a preferred example, during the downward punching of the blank 2 by the upper punch 1, a back pressure is provided to the blank below the portion of the blank 2 punched by the upper punch.
Preferably, the magnitude of the back pressure is set according to formula (1):
F=5×10 6 ×s type (1)
Wherein F represents the back pressure, and S represents the preset bottom area of the convex hull.
The back pressure is set according to the preset area of the bottom of the convex hull, and the larger the preset area of the bottom of the convex hull is, the larger the back pressure is provided. The material flow can be effectively slowed down in the extrusion process, so that the material plate material is slowly extruded into the lower die stamping female die to slowly form a convex hull, and the material is prevented from cracking due to rapid stretching.
Preferably, as shown in fig. 1, a push rod 4 is arranged in the lower die stamping concave die 3, and a driving piece is connected below the push rod 4. The driving member may employ a compression spring. In the process of punching the material plate 2 by the upper die punch 1, under the thrust action of the upper die punch 1, the ejector rod 4 descends to compress the compression spring, and the compression spring provides back pressure for the material plate 2 through the ejector rod 4.
In the embodiment, a push rod 4 is arranged in a lower die stamping female die 3. When the material plate 2 is placed, the ejector rod 4 plays a role in receiving the material plate. The ejector rod 4 is contacted with the bottom surface of the material plate. In the process of pressing down the upper die punch 1, the ejector rod 4 descends along with the upper die punch 1 and provides back pressure for the material plate 2. After the stamping forming, the ejector rod 4 also plays a role in pushing the convex hull out of the lower die stamping female die.
As a preferable example, the upper punch 1 has steps of upper thickness and lower thickness.
Preferably, the upper die punch 1 comprises a first punching shaft and a second punching shaft, the second punching shaft is arranged at the top end of the first punching shaft, the diameter of the second punching shaft is larger than that of the first punching shaft, and a step is formed at the joint of the first punching shaft and the second punching shaft.
In the process of pressing the material plate 2 into the lower die stamping female die by the upper die punch head 1, if the height of the convex hull does not reach the preset height after the bottom of the second stamping shaft reaches the upper surface of the material plate, the upper die punch head continues to descend, and the second stamping shaft presses part of the material in the thickness of the material plate into the lower die stamping female die. The upper die punch is provided with a step structure with a thick upper part and a thin lower part, part of materials on the thickness of the material plate are extruded into the lower die stamping concave die to form a convex hull, as shown in fig. 3, the effective height of the convex hull is increased, and meanwhile the risk of cracking of the side wall of the convex hull is reduced. In the step structure, the bottom surface of the second stamping shaft is an annular surface. And in the working process of the second stamping shaft, extruding part of the material on the thickness of the material plate into the lower die stamping female die by virtue of the bottom surface of the second stamping shaft. In the process, the side wall of the first stamping shaft plays a limiting role, and the lower die stamping concave die 3 also plays a limiting role, so that materials extruded by the bottom surface of the second stamping shaft are all used for forming the convex hull. Meanwhile, the bottom surface of the second stamping shaft is an annular surface, and materials are uniformly extruded into the lower die stamping female die along the circumferential direction, so that the materials forming the convex hulls are distributed more uniformly, and the qualification rate of products is improved.
Preferably, the second stamping shaft presses the web down to a height no greater than half the thickness of the web. The material in the thickness can be sheared to supplement and form the convex hull, the effective height of the convex hull is increased, the material strength of the root of the convex hull is not influenced, and the requirements on the height and the strength of the convex hull are met.
Preferably, the diameter difference between the second punching shaft and the first punching shaft is 2 to 2.4mm.
The convex hull forming process for the high-strength large-thickness material adopts an extrusion process to form the convex hull in one step. As shown in fig. 2, the method specifically comprises the following steps:
The material plate 2 is placed on the lower die stamping female die 3, and the ejector rod 4 in the lower die stamping female die 3 abuts against the lower surface of the material plate 2.
The upper die punch 1 descends, the bottom end of the first punching shaft continuously descends to apply pressure to the material plate after contacting the material plate 2, the compression spring provides back pressure for the material plate 2 through the ejector rod 4, the back pressure is smaller than the downward pressure of the upper die punch, the material plate 2 and the ejector rod 4 are pushed to move downwards by the first punching shaft, and the material plate 2 is slowly extruded into the lower die punching concave die to gradually form a convex hull.
If the bottom of the second stamping shaft does not reach the upper surface of the material plate yet and the height of the convex hull reaches the preset height, the upper die stamping head 1 is lifted, the ejector rod 4 is lifted under the action of the compression spring, and the convex hull is pushed out of the lower die stamping die to obtain the convex hull with the preset size.
If the height of the convex hull does not reach the preset height after the bottom of the second punching shaft reaches the upper surface of the material plate, the upper die punch 1 continues to descend, and the second punching shaft extrudes part of the material on the thickness of the material plate into the lower die punching concave die to form the convex hull, so that the height of the convex hull reaches the preset height. In the process, the first stamping shaft descends to increase the height of the convex hull, and simultaneously, the second stamping shaft descends synchronously with the first stamping shaft to squeeze part of the material on the thickness of the material plate into the stamping female die of the lower die. In the process of increasing the height of the convex hull, the second stamping shaft synchronously supplements materials for the convex hull, namely materials descending by extruding the material plate from the bottom surface of the second stamping shaft, so that the thickness of the convex hull meets the requirement, and the side wall of the convex hull is prevented from being pulled apart. The upper die punch 1 ascends, the ejector rod 4 ascends under the action of the compression spring, and the convex hull is pushed out of the lower die stamping die to obtain the convex hull with the preset size.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the present invention.
Claims (3)
1. A convex hull forming process for high-strength large-thickness materials is characterized in that an extrusion process is adopted to form a convex hull in one step; a push rod is arranged in the lower die stamping female die, and a driving piece is connected below the push rod;
The convex hull is formed by adopting an extrusion process through one-step molding, and specifically comprises the following steps:
Placing the material plate on a lower die stamping female die, wherein an upper die stamping head descends to stamp the material plate, and in the process that the upper die stamping head downwards stamps the material plate, a push rod descends and always abuts against the material plate, and a driving piece provides back pressure for the material plate below the stamping position of the material plate by the upper die stamping head through the push rod; extruding the material plate into a lower die stamping female die to form a convex hull with a preset height; the material flow can be effectively slowed down in the extrusion process, so that the material plate material is slowly extruded into the stamping female die of the lower die to slowly form a convex hull, and the material is prevented from cracking due to rapid stretching; the upper die punch is matched with the lower die stamping female die; the thickness of the material plate is 3-5 mm, and the tensile strength of the material plate is 355-700 MPa;
the magnitude of the back pressure is set according to formula (1):
(1)
Wherein F represents back pressure, S represents the preset bottom area of the convex hull;
the upper die punch head is provided with steps with thick upper part and thin lower part; the upper die punch comprises a first punching shaft and a second punching shaft, the second punching shaft is arranged at the top end of the first punching shaft, the diameter of the second punching shaft is larger than that of the first punching shaft, and a step is formed at the joint of the first punching shaft and the second punching shaft; the diameter difference between the second punching shaft and the first punching shaft is 2-2.4 mm.
2. The process for forming a convex hull for a high-strength and large-thickness material according to claim 1, wherein the upper punch descends to press the material plate, and the second punch presses a part of the material in the thickness of the material plate into the lower die to press the material plate into the lower die if the convex hull height does not reach a predetermined height after the bottom of the second punch reaches the upper surface of the material plate.
3. The convex hull forming process for high strength, high thickness material according to claim 2, wherein the second pressing shaft presses the web down to a height not greater than half the thickness of the web.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311823919.6A CN117483531B (en) | 2023-12-28 | 2023-12-28 | Convex hull forming process for high-strength large-thickness material |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311823919.6A CN117483531B (en) | 2023-12-28 | 2023-12-28 | Convex hull forming process for high-strength large-thickness material |
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| CN117483531A CN117483531A (en) | 2024-02-02 |
| CN117483531B true CN117483531B (en) | 2024-04-16 |
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| CN202311823919.6A Active CN117483531B (en) | 2023-12-28 | 2023-12-28 | Convex hull forming process for high-strength large-thickness material |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4373369A (en) * | 1980-03-27 | 1983-02-15 | Modine Manufacturing Company | Method of forming integral flanges in a sheet |
| CN102935578A (en) * | 2012-10-18 | 2013-02-20 | 江苏大学 | Method for manufacturing local boss nut plate by high-intensity biphase steel plate |
| CN208033432U (en) * | 2017-12-29 | 2018-11-02 | 州巧科技股份有限公司 | Metal plate with positioning salient points and forming device of positioning salient points |
| CN212264292U (en) * | 2020-03-23 | 2021-01-01 | 苏州平山精密部件有限公司 | Thick material sprouting mold structure |
| CN215845220U (en) * | 2021-07-12 | 2022-02-18 | 怡景(上海)五金制品有限公司 | Impact extrusion punch and impact extrusion die with positioning boss |
| CN114603044A (en) * | 2022-03-23 | 2022-06-10 | 漳州锐腾电器有限公司 | Hardware mold for material-increasing extrusion forming of bulges and forming method of bulges |
-
2023
- 2023-12-28 CN CN202311823919.6A patent/CN117483531B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4373369A (en) * | 1980-03-27 | 1983-02-15 | Modine Manufacturing Company | Method of forming integral flanges in a sheet |
| CN102935578A (en) * | 2012-10-18 | 2013-02-20 | 江苏大学 | Method for manufacturing local boss nut plate by high-intensity biphase steel plate |
| CN208033432U (en) * | 2017-12-29 | 2018-11-02 | 州巧科技股份有限公司 | Metal plate with positioning salient points and forming device of positioning salient points |
| CN212264292U (en) * | 2020-03-23 | 2021-01-01 | 苏州平山精密部件有限公司 | Thick material sprouting mold structure |
| CN215845220U (en) * | 2021-07-12 | 2022-02-18 | 怡景(上海)五金制品有限公司 | Impact extrusion punch and impact extrusion die with positioning boss |
| CN114603044A (en) * | 2022-03-23 | 2022-06-10 | 漳州锐腾电器有限公司 | Hardware mold for material-increasing extrusion forming of bulges and forming method of bulges |
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| CN117483531A (en) | 2024-02-02 |
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