CN116967327A - Hydraulic forming device and hydraulic forming method for hollow inner sleeve - Google Patents
Hydraulic forming device and hydraulic forming method for hollow inner sleeve Download PDFInfo
- Publication number
- CN116967327A CN116967327A CN202311117095.0A CN202311117095A CN116967327A CN 116967327 A CN116967327 A CN 116967327A CN 202311117095 A CN202311117095 A CN 202311117095A CN 116967327 A CN116967327 A CN 116967327A
- Authority
- CN
- China
- Prior art keywords
- corrugated pipe
- metal corrugated
- inner sleeve
- hollow inner
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000002184 metal Substances 0.000 claims abstract description 161
- 238000002347 injection Methods 0.000 claims abstract description 38
- 239000007924 injection Substances 0.000 claims abstract description 38
- 238000007789 sealing Methods 0.000 claims description 111
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 59
- 238000007599 discharging Methods 0.000 claims description 6
- 238000003825 pressing Methods 0.000 claims description 5
- 238000013459 approach Methods 0.000 claims description 4
- 238000013461 design Methods 0.000 claims description 4
- 230000007704 transition Effects 0.000 claims description 3
- 239000000463 material Substances 0.000 description 7
- 210000004907 gland Anatomy 0.000 description 3
- 239000002356 single layer Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D15/00—Corrugating tubes
- B21D15/12—Bending tubes into wave form
Abstract
The invention belongs to the technical field of metal corrugated pipe hydroforming, and particularly relates to a hollow inner sleeve hydroforming device and a hydroforming method thereof, wherein the hollow inner sleeve and an outer mold are included; the hollow inner sleeve is arranged in the metal corrugated pipe blank and is sealed with the inner wall of the metal corrugated pipe blank, a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the hollow inner sleeve is connected with an exhaust pipe and an injection pipe, and the exhaust pipe and the injection pipe are communicated to the sealed space; the outer parts of the metal corrugated pipe blanks are provided with outer dies which assist in forming corrugated pipes at two ends, and one end of each metal corrugated pipe blank is provided with a pressure head which pushes towards the other end of the metal corrugated pipe blank. The invention empties the effective area in the metal corrugated pipe in a large quantity, obviously reduces the internal pressure thrust during hydraulic forming, realizes the hydraulic forming of the large-diameter thick-wall metal corrugated pipe on a smaller-tonnage hydraulic machine, and effectively solves the problem that the large-diameter thick-wall corrugated pipe has no large-tonnage hydraulic machine.
Description
Technical Field
The invention belongs to the technical field of metal corrugated pipe hydroforming, and particularly relates to a hollow inner sleeve hydroforming device and a hydroforming method thereof.
Background
Hydroforming is one of the important process methods for manufacturing metal bellows. Metal bellows for large diameter thick wall pressure vessels often need to be completed on particularly large tonnage hydraulic press equipment. Large tonnage hydraulic press equipment is generally high in cost and is difficult to be widely popularized and applied in the industry. Therefore, the hydraulic forming process of the metal corrugated pipe for the large-diameter thick-wall pressure vessel is a technical problem in the industry.
Disclosure of Invention
In view of the above problems in the prior art, the present invention has an object of researching and designing a novel hollow inner sleeve hydroforming device. The hydraulic forming device is used for solving the problems that in the prior art, when a large-diameter thick-wall metal corrugated pipe for a pressure container is formed by hydraulic forming, the axial pressure is overlarge, a large-tonnage hydraulic press is needed, and a forming process cannot be completed by the insufficient hydraulic press.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the hollow inner sleeve hydroforming device comprises a hollow inner sleeve and an outer die; the hollow inner sleeve is arranged in the metal corrugated pipe blank and is sealed with the inner wall of the metal corrugated pipe blank, a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the hollow inner sleeve is connected with an exhaust pipe and an injection pipe, and the exhaust pipe and the injection pipe are communicated to the sealed space; the outer parts of the metal corrugated pipe blanks are provided with outer dies which assist in forming corrugated pipes at two ends, and one end of each metal corrugated pipe blank is provided with a pressure head which pushes towards the other end of the metal corrugated pipe blank.
Further, sealing covers are arranged between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the two sealing covers are respectively positioned at the upper end and the lower end of the metal corrugated pipe blank, the outer diameter of each sealing cover is sealed with the inner wall of the metal corrugated pipe blank through an outer sealing ring, the inner diameter of each sealing cover is sealed with the outer wall of the hollow inner sleeve through an inner sealing ring, and the inner wall of the metal corrugated pipe blank, the outer wall of the hollow inner sleeve and the two sealing covers are enclosed to form a sealing space.
Further, the outer side end surfaces of the two sealing covers are respectively flush with the end surfaces of the upper end and the lower end of the metal corrugated pipe blank; the outer sealing ring and the inner sealing ring are respectively positioned at the inner side end faces of the two sealing covers, and the outer sealing ring and the inner sealing ring are Y-shaped sealing rings.
Further, the hydraulic forming device for the hollow inner sleeve further comprises a working platform, wherein the end face of the lower end of the metal corrugated pipe blank is arranged on the working platform, and the pressure head is contacted with the end face of the upper end of the metal corrugated pipe blank and is pressed down to be close to the working platform.
Further, the outer side end surfaces of the two outer dies are flush with the end surfaces of the upper end and the lower end of the metal corrugated pipe blank, and are respectively attached to the working platform and the working surface of the pressure head.
Further, the inner diameter corners of the inner side end surfaces of the two outer dies are in arc transition.
Further, a bypass overflow valve is arranged on the injection pipe; valves for controlling on-off are arranged on the exhaust pipe and the injection pipe.
The invention discloses a hydraulic forming device for a hollow inner sleeve, and relates to a hydraulic forming process device for a metal corrugated pipe. The hydraulic press comprises a metal corrugated pipe blank to be formed and a hollow inner sleeve in the metal corrugated pipe blank, wherein a water inlet pressurizing injection pipe and an exhaust pipe for exhausting are arranged between a hydraulic press working platform and a pressure head; sealing rings are arranged between the two ends of the inner side of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the outer part of the sealing rings is in sealing fit with the inner wall of the metal corrugated pipe, the inner side of the sealing rings is in sealing fit with the outer wall of the hollow inner sleeve, and Y-shaped sealing rings are arranged at the inner and outer fitting positions; external dies are arranged at two ends of the outer part of the metal corrugated pipe. The invention has the function of evacuating the effective area of the metal corrugated pipe, can effectively reduce the internal pressure thrust during the forming of the large-diameter thick-wall corrugated pipe, reduce the requirement on the tonnage of the hydraulic press, effectively solve the problem that the large-diameter thick-wall metal corrugated pipe is not formed by the hydraulic press with large tonnage, and is a unique dry and large-activity hydraulic forming process method with small equipment.
The forming method of the hydraulic forming device of the hollow inner sleeve is that the inner space of the metal corrugated pipe blank is removed through the hollow inner sleeve, so that a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve to be an effective area for generating internal pressure, high-pressure water is injected into the sealed space through an injection pipe when the metal corrugated pipe is formed, and a pressure head is axially pushed along the metal corrugated pipe blank until the final shape and size requirements of the metal corrugated pipe are met.
When the metal corrugated pipe is formed, firstly, water is injected into a sealed space between the metal corrugated pipe blank and the hollow inner sleeve through a water injection pipe, and exhaust is carried out through an exhaust pipe; after the sealed space is filled with water, a valve on the exhaust pipe is closed, and then the water injection pipe is pressurized by a high-pressure water pump, when the pressure reaches the initial forming pressure, the high-pressure water injection valve is closed, the hydraulic press is pushed down along the axial direction of the metal corrugated pipe blank by the pressure head, the internal pressure is gradually increased, the bulge of the metal corrugated pipe blank is gradually increased, the pressure in the cavity is controlled to be at the set pressure required by forming by a bypass overflow valve of the water injection pipe, and the redundant water is discharged out of the cavity; the pressure head continues to move downwards for pressurization, and the forming amplitude of the metal corrugated pipe gradually approaches to the finished product state until the design state of the metal corrugated pipe is finally reached.
Further, when the pressure reaches the initial forming pressure, namely, when the metal corrugated pipe blank starts to bulge at the middle sections of the upper outer mold and the lower outer mold.
Further, after the metal corrugated pipe is formed, a bypass overflow valve is opened to discharge the pressure to zero, water in the cavity is discharged, the pressure head is moved upwards, the outer die and the sealing ring are sequentially discharged, the finished metal corrugated pipe is taken out from the workbench, and the forming is completed.
Further, the metal corrugated pipe blank is expanded outwards along the arc corners of the two outer dies during forming to form the metal corrugated pipe.
Further, the formed metal bellows is a single wave metal bellows.
The concrete method for forming the metal corrugated pipe by adopting the hollow inner sleeve hydraulic forming device comprises the following steps:
1) Placing the workbench on a movable workbench of a hydraulic machine, or directly using the movable workbench of the hydraulic machine as a hydraulic forming workbench;
2) Mounting the hollow inner sleeve on a workbench;
3) Assembling the lower part of the lower sealing ring to the outside of the hollow inner sleeve and the workbench;
4) Assembling the metal corrugated pipe blank outside the sealing ring and on the workbench;
5) Assembling the lower part of the outer die to the outside of the metal corrugated pipe blank and the workbench;
6) Assembling the lower sealing ring into a groove between the lower sealing ring and the hollow inner sleeve as well as the metal corrugated pipe blank;
7) And the upper sealing ring of the upper sealing ring is arranged between the metal corrugated pipe blank and the hollow inner sleeve.
8) And assembling the upper part of the outer mold to the outside of the metal corrugated pipe blank.
9) The upper beam of the hydraulic press is moved downwards, and a pressure head is arranged on the upper beam, so that the pressure head is abutted against the upper part of the outer die, the upper part of the upper sealing ring and the upper end surface of the metal corrugated pipe blank;
10 Water is injected into a cavity between the metal corrugated pipe blank and the hollow inner sleeve through the water injection pipe, and exhaust is carried out through the exhaust pipe;
11 After the cavity is filled with water, the valve on the exhaust pipe is closed, then the water injection pipe is used for pressurizing by the high-pressure water pump, when the pressure reaches the initial forming pressure (the metal corrugated pipe blank just starts to bulge at the middle sections of the upper and lower outer dies), the water injection valve of the high-pressure pump is closed, the upper beam of the hydraulic press starts to slowly move downwards through the pressure head, the water pressure in the cavity moves downwards along with the pressure head, the internal pressure is gradually increased, the bulge of the metal corrugated pipe blank is gradually increased, the pressure in the cavity is controlled to be at the set pressure required by forming by the bypass overflow valve of the water injection pipe, and the redundant water is discharged out of the cavity. The pressure head continues to move downwards for pressurization, and the forming amplitude of the metal corrugated pipe gradually approaches to the finished product state until the metal corrugated pipe finally reaches the design state;
12 After the metal corrugated pipe is formed, opening a bypass valve to discharge the pressure to zero, discharging water in the cavity, moving the pressure head upwards, sequentially discharging the outer mold and the sealing ring, taking the finished metal corrugated pipe out of the workbench, and forming.
The beneficial effects of the invention are as follows: the invention provides a hydraulic forming device with a hollow inner sleeve, wherein the hollow inner sleeve is arranged in a metal corrugated pipe to be formed, two ends of a workpiece and the hollow inner sleeve are sealed by an upper sealing gland, a lower sealing gland and a sealing ring, and the effective area in the metal corrugated pipe is largely emptied, so that the internal pressure thrust in the hydraulic forming process is remarkably reduced, the hydraulic forming of a large-diameter thick-wall metal corrugated pipe on a smaller-tonnage hydraulic machine is realized, and the problem that the large-diameter thick-wall corrugated pipe is free of the large-tonnage hydraulic machine is effectively solved.
Drawings
FIG. 1 is a state diagram of a hollow inner sleeve hydroforming device of the present invention prior to forming;
FIG. 2 is a state diagram of the hollow inner sleeve hydroforming device of the present invention after being formed;
in the figure: 1. the sealing device comprises an outer die 2, a metal corrugated pipe 3, a sealing cover 4, a hollow inner sleeve 5, an exhaust pipe 6, an injection pipe 7, a working platform 8, a pressure head 9, an inner sealing ring 10 and an outer sealing ring.
Detailed Description
In order to make the structure and function of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiment of the present invention.
Referring to fig. 1-2, a hollow inner sleeve hydroforming device comprises a hollow inner sleeve and an outer mold; the hollow inner sleeve is arranged in the metal corrugated pipe blank and is sealed with the inner wall of the metal corrugated pipe blank, a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the hollow inner sleeve is connected with an exhaust pipe and an injection pipe, and the exhaust pipe and the injection pipe are communicated to the sealed space; the outer parts of the metal corrugated pipe blanks are provided with outer dies which assist in forming corrugated pipes at two ends, and one end of each metal corrugated pipe blank is provided with a pressure head which pushes towards the other end of the metal corrugated pipe blank.
Further, sealing covers are arranged between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the two sealing covers are respectively positioned at the upper end and the lower end of the metal corrugated pipe blank, the outer diameter of each sealing cover is sealed with the inner wall of the metal corrugated pipe blank through an outer sealing ring, the inner diameter of each sealing cover is sealed with the outer wall of the hollow inner sleeve through an inner sealing ring, and the inner wall of the metal corrugated pipe blank, the outer wall of the hollow inner sleeve and the two sealing covers are enclosed to form a sealing space.
Further, the outer side end surfaces of the two sealing covers are respectively flush with the end surfaces of the upper end and the lower end of the metal corrugated pipe blank; the outer sealing ring and the inner sealing ring are respectively positioned at the inner side end faces of the two sealing covers, and the outer sealing ring and the inner sealing ring are Y-shaped sealing rings.
Further, the hydraulic forming device for the hollow inner sleeve further comprises a working platform, wherein the end face of the lower end of the metal corrugated pipe blank is arranged on the working platform, and the pressure head is contacted with the end face of the upper end of the metal corrugated pipe blank and is pressed down to be close to the working platform.
Further, the outer side end surfaces of the two outer dies are flush with the end surfaces of the upper end and the lower end of the metal corrugated pipe blank, and are respectively attached to the working platform and the working surface of the pressure head.
Further, the inner diameter corners of the inner side end surfaces of the two outer dies are in arc transition.
Further, a bypass overflow valve is arranged on the injection pipe; valves for controlling on-off are arranged on the exhaust pipe and the injection pipe.
The hollow inner sleeve hydroforming device comprises a hollow inner sleeve; sealing cover; a seal ring; an outer mold; a working platform; a pressure head. The hollow inner sleeve hydroforming device is arranged above the working platform 5 and below the pressure head 6. In the hydraulic forming device for the hollow inner sleeve, the hollow inner sleeve 4 is arranged in a metal corrugated pipe blank 2; sealing covers 3 are arranged at the upper end and the lower end between the inner wall of the metal corrugated pipe blank 2 and the outer diameter of the hollow inner sleeve 4, an outer sealing ring 10 is arranged between the sealing cover 3 and the metal corrugated pipe blank 2, and an inner sealing ring 9 is arranged between the sealing cover 3 and the outer cylindrical surface of the hollow inner sleeve 4. The upper end and the lower end of the straight edge outer diameter of the metal corrugated pipe blank 2 are respectively provided with an outer die 1, and the end faces of the upper outer die 1 and the lower outer die 1 are flush with the two ends of the metal corrugated pipe blank 2 and are respectively attached to working faces of a working platform 7 and a pressure head 8. In the hydraulic forming device for the hollow inner sleeve, an exhaust pipe 5 and an injection pipe 6 are respectively arranged on the inner wall of the hollow inner sleeve 4.
The outer dies are sleeved outside two ends of the metal corrugated pipe blank to be formed and are used for limiting expansion deformation of the metal corrugated pipe blank under the action of high-pressure water; the hollow inner sleeve is placed in the metal corrugated pipe blank, a sealing cover is arranged between the hollow inner sleeve and the metal corrugated pipe blank, sealing rings are respectively arranged between the sealing cover and the metal corrugated pipe blank and between the sealing cover and the hollow inner sleeve, and an annular sealing space is formed by the metal corrugated pipe blank, the sealing cover, the inner sealing ring, the outer sealing ring and the hollow inner sleeve; the annular area between the hollow inner sleeve and the metal corrugated pipe blank is the effective area for generating the internal pressure, and the effective area of the metal corrugated pipe is emptied by the majority of the hollow inner sleeve, so that the pressure required by the hydraulic forming of the metal corrugated pipe is greatly reduced.
The forming method of the hydraulic forming device of the hollow inner sleeve is that the inner space of the metal corrugated pipe blank is removed through the hollow inner sleeve, so that a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve to be an effective area for generating internal pressure, high-pressure water is injected into the sealed space through an injection pipe when the metal corrugated pipe is formed, and a pressure head is axially pushed along the metal corrugated pipe blank until the final shape and size requirements of the metal corrugated pipe are met. The formed metal corrugated pipe is a single wave metal corrugated pipe.
The concrete method for forming the metal corrugated pipe by adopting the hollow inner sleeve hydraulic forming device comprises the following steps:
as shown in figure 1 of the drawings,
1) Placing the workbench 7 on a movable workbench of a hydraulic machine, or directly using the movable workbench of the hydraulic machine as a hydraulic forming workbench;
2) Mounting the hollow inner sleeve 4 on a workbench 7;
3) Assembling the sealing ring 3 (below) to the outside of the hollow inner sleeve 4 and to the table 7;
4) Assembling the metal corrugated pipe blank 2 outside the sealing ring 3 and on the workbench 7;
5) Assembling the outer die 1 (lower part) on the outside of the metal corrugated pipe blank 2 and a workbench;
6) Assembling a sealing ring 9/10 (lower part) into a groove between the sealing ring (lower part) and the hollow inner sleeve 4 and the metal corrugated pipe blank 2;
7) Installing a sealing ring 3 (upper part) and a sealing ring 9/10 (upper part) between the metal corrugated pipe blank 2 and the hollow inner sleeve 4;
8) Assembling the outer mold 1 (upper part) to the outside of the metal corrugated pipe blank;
9) The upper beam of the hydraulic press is moved downwards (the pressing head 8 is arranged on the upper beam) so that the pressing head 8 is abutted against the upper end face of the outer die 1 (upper part), the sealing ring 3 (upper part) and the metal corrugated pipe blank 2;
10 Water is injected into the cavity between the metal corrugated pipe blank 2 and the hollow inner sleeve 4 through the water injection pipe 6, and exhaust is carried out through the exhaust pipe 5;
11 After the cavity is filled with water, the valve on the exhaust pipe is closed, then the water injection pipe 6 is used for pressurizing by a high-pressure water pump, when the pressure reaches the initial forming pressure (the metal corrugated pipe blank just starts to bulge in the middle section of the upper and lower outer dies 1), the water injection valve of the high-pressure water pump is closed, the upper beam of the hydraulic press starts to slowly move downwards through the pressure head 8, the water pressure in the cavity moves downwards along with the pressure head, the inner pressure is gradually increased, the bulge of the metal corrugated pipe blank is gradually increased, the pressure in the cavity is controlled to be at the set pressure required by forming through the bypass overflow valve of the water injection pipe, and redundant water is discharged out of the cavity. The pressure head 8 continues to move downwards for pressurization, and the forming amplitude of the metal corrugated pipe gradually approaches to the finished product state until the metal corrugated pipe reaches the design state finally;
12 After the metal corrugated pipe is formed, as shown in the state of fig. 2, opening a bypass valve to discharge the pressure to zero, discharging water in the cavity, moving the pressure head upwards, sequentially discharging the outer die 1 and the sealing ring 3, taking out the finished metal corrugated pipe from the workbench 8, and forming.
The following description is provided in connection with specific formulas and operations.
1. Hydraulic forming process and stress calculation for metal corrugated pipe
1. Hydraulic forming process of metal corrugated pipe
The common metal corrugated pipe hydraulic forming tool is shown in fig. 1, and mainly comprises an outer die, a sealing cover, a pressure head, a working platform, a sealing ring and the like, wherein the outer parts of two ends of a corrugated pipe blank needing to be formed are fixed by the outer die and are limited to expand outwards, and the straight edge sections of the two inner ends are sealed by the sealing gland and the sealing ring. The lower part is arranged on a working platform of the hydraulic machine, and the upper part is pressed by a pressing head. Meanwhile, the device is provided with a high-pressure water injection pump, a pressure gauge, a water drain valve, a water tank, a high-pressure water pipe, a sealing joint and the like.
The necessary conditions for hydroforming the thick-wall metal corrugated pipe for the pressure vessel are as follows: a hydraulic machine with a large enough tonnage is required, while the hydraulic machine has a large enough working table and proper stroke and closing clearance. The high-pressure water injection pump is provided with a plunger type high-output pressure, two pressure gauges suitable for forming pressure ranges are provided, the pressure range of the pressure gauges is 2-4 times of the forming pressure, and the pressure of the water inlet pipe, the water drain pipe, the air release valve, the water drain valve, the sealing joint and the like are suitable.
When forming, high-pressure water is injected into the inner cavity of the workpiece by a high-pressure water pump, and when the water pressure reaches the initial pressure required by forming, the workpiece begins to bulge and deform under the action of the internal pressure, and the initial positioning block is removed in time. Along with the continuous rising of water pressure, the bulge deformation of the corrugated pipe blank is gradually increased, the hydraulic press is matched with the workpiece deformation to follow in the axial direction, the descending speed or the follow-up position of the hydraulic press slide block is closely matched with the gradual bulge and the length shrinkage of the corrugated pipe, and the working surface of the working table surface and the pressure head are always kept close to the two ends of the pipe blank for compaction. With the gradual increase of the expansion degree of the corrugation, the hydraulic press continuously follows and axially compresses the workpiece, the forming water pressure is also gradually increased, and at the moment, the overflow valve is matched with the forming machine to drain excessive water while maintaining the required forming pressure until the final shape and size requirements of the metal corrugated pipe are met.
2. Calculation of internal pressure required for shaping
The internal pressure required for the bellows molding is:
wherein: p (P) n -calculating the internal pressure (MPa) required for the formation
k n -yield coefficient. The actual yield limit of the material and the yield limit at normal temperature are related, and are generally between 1.25 and 1.5. Specifically, the method can be obtained through actual measurement.
σ s -material yield limit (MPa) at normal temperature
Delta-nominal thickness of monolayer material (mm)
n-layer number
Di-corrugated pipe straight edge inner diameter (mm)
The initial forming pressure is as follows:
P nc ＝K c P n (2)
wherein: p (P) nC Initial internal pressure (MPa) required for shaping
k c The initial pressure coefficient can be calculated from 1.0 to 1.1.
The forming termination pressure is:
P nz ＝K z P n (3)
wherein: p (P) nz The internal pressure (MPa) required for forming
k z The termination pressure coefficient, which is dependent on factors such as material, waveform size, etc., can generally be calculated in the range of 1.8 to 2.2.
3. Internal pressure thrust calculation
For the conventional forming process and tooling, when the wave height of the corrugated pipe reaches the maximum value and the forming is in a final state, the generated internal pressure thrust is maximum, and the value is as follows:
F n ＝P nz S y (4)
wherein: f (F) n Maximum internal pressure (N)
P nz -forming the final desired internal pressure (MPa)
Sy-effective area of bellows (mm) 2 )
D m Average diameter (mm) of bellows
4. Work piece axial yield force calculation
F q ＝σ s k n W/h y (6)
W＝π(D i +δ)δ 2 n/6 (7)
h y ＝hk h (8)
Wherein: f (F) P -axial yield force (N) of bellows
σ s -material yield limit (MPa) at normal temperature
k n -yield coefficient, 1.25-1.5, or obtained according to the test.
W-modulus of bending section (mm) of corrugated pipe 3 )
h y -forming process yield force calculation height (mm)
Di-corrugated pipe straight edge inner diameter (mm)
Delta-nominal thickness of monolayer material (mm)
n-layer number
k h -calculating coefficients, initially taking 0.3-0.4; finally taking 0.5 to 0.7, or obtaining according to actual measurement
5. Hydroforming total axial calculation
F＝F n +F p (9)
For conventional forming processes, the internal pressure thrust required for thick-walled metal bellows is particularly high when the bellows is large in diameter. Therefore, hydraulic presses with large tonnage are required for the operation.
For example: the straight edge inner diameter of the metal corrugated pipe for the single-layer thick-wall pressure container is 2500mm, the wall thickness is 28mm, the material is Q345R, and the calculated internal pressure thrust force exceeds 13000 tons and the total axial force is approximately 15000 tons.
2. Hollow inner sleeve hydroforming tool and stress calculation
1. When the forming tool of the hollow inner sleeve is adopted, as the hollow inner sleeve is arranged in the corrugated pipe, the sealing covers and the sealing rings are respectively arranged at the two ends in the corrugated pipe, the outer sealing ring is arranged between the sealing covers and the metal corrugated pipe blank workpiece, the inner sealing ring is arranged between the sealing covers and the outer wall of the hollow outer sleeve, the effective area of the corrugated pipe is largely emptied by the hollow inner sleeve, the internal pressure thrust during forming is obviously reduced, and the hydraulic forming work can be completed satisfactorily without using a large tonnage hydraulic press.
2. Internal pressure thrust calculation
F z ＝P nz (S y -S x ) (10)
Wherein: f (F) z Maximum internal pressure (MPa)
P nz The internal pressure (MPa) required for forming
S y -bellows limited area (mm) 2 )
S x Hollow inner sleeve outer circular cross-section area (mm) 2 )
D x -outer diameter of hollow tube (mm)
When the diameter of the hollow inner sleeve (D x ) The closer to the straight edge inner diameter (D m ) In this case, the internal pressure thrust decreases more.
3. The work piece axial yield force calculation is the same as the common forming process.
4. Friction calculation
When the hollow inner sleeve device is adopted, a sealing ring is arranged between the sealing cover and the outer surface of the hollow inner sleeve, when the corrugated pipe is axially compressed, axial displacement can occur between the upper sealing cover and the hollow inner sleeve, under the action of forming high-pressure water, the surface of the sealing ring and the outer surface of the hollow inner sleeve have higher compression force, and when the sealing ring and the outer surface of the hollow inner sleeve axially move, friction force can be generated.
F f ＝πP nz D y bμ (12)
Wherein: f (F) f Friction force (KN)
p nz The internal pressure (MPa) required for forming
D y -hollow jacket outer diameter (mm)
b-width of seal ring (mm)
Mu-coefficient of friction
5. Hydroforming total axial force calculation
F＝F z +F p +F f (13)
For the above example, if the hollow inner sleeve hydroforming tool is used, the internal pressure thrust is still less than 3000 tons when the outer diameter of the hollow outer sleeve is 2380 mm. At this time, the total axial force of the hydroforming comprises the internal pressure pushing force and the axial bending force of the corrugated pipe, and the friction force of the upper sealing ring and the hollow inner sleeve. Because the internal pressure thrust is greatly reduced, the axial yield force of the corrugated pipe is consistent with that of the conventional hydroforming method, the friction force between the upper sealing ring and the surface of the hollow inner sleeve is small, and the total hydroforming axial force is less than about 5000 tons and is only about 1/3 of that of the conventional hydroforming method through calculation.
Conclusion: the hollow inner sleeve tool is used for hydraulic forming of the thick-wall metal corrugated pipe of the pressure container, the effective area of the corrugated pipe is largely emptied, so that the internal pressure thrust during forming is greatly reduced, and the difficult problem of a large-tonnage-free hydraulic machine for forming the thick-wall corrugated pipe with a large diameter can be solved by using a small-tonnage hydraulic machine.
It should be noted that the detailed portions of the present invention are not described in the prior art.
The foregoing list is only the preferred embodiments of the present invention. Obviously, the invention is not limited to the above embodiments, but many variations are possible. All modifications directly derived or suggested to one skilled in the art from the present disclosure should be considered as being within the scope of the present invention.
Claims (10)
1. The hollow inner sleeve hydraulic forming device is characterized in that: comprises a hollow inner sleeve and an outer mold; the hollow inner sleeve is arranged in the metal corrugated pipe blank and is sealed with the inner wall of the metal corrugated pipe blank, a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the hollow inner sleeve is connected with an exhaust pipe and an injection pipe, and the exhaust pipe and the injection pipe are communicated to the sealed space; the outer parts of the metal corrugated pipe blanks are provided with outer dies which assist in forming corrugated pipes at two ends, and one end of each metal corrugated pipe blank is provided with a pressure head which pushes towards the other end of the metal corrugated pipe blank.
2. The hollow inner sleeve hydroforming device according to claim 1, wherein: the sealing device is characterized in that sealing covers are arranged between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve, the two sealing covers are respectively arranged at the upper end and the lower end of the metal corrugated pipe blank, the outer diameter of each sealing cover is sealed with the inner wall of the metal corrugated pipe blank through an outer sealing ring, the inner diameter of each sealing cover is sealed with the outer wall of the hollow inner sleeve through an inner sealing ring, and the inner wall of the metal corrugated pipe blank, the outer wall of the hollow inner sleeve and the two sealing covers enclose to form a sealing space.
3. The hollow inner sleeve hydroforming device according to claim 2, wherein: the outer side end surfaces of the two sealing covers are respectively flush with the end surfaces of the upper end and the lower end of the metal corrugated pipe blank; the outer sealing ring and the inner sealing ring are respectively positioned at the inner side end faces of the two sealing covers, and the outer sealing ring and the inner sealing ring are Y-shaped sealing rings.
4. The hollow inner sleeve hydroforming device according to claim 1, wherein: the metal corrugated pipe blank pressing device further comprises a working platform, wherein the end face of the lower end of the metal corrugated pipe blank is arranged on the working platform, and the pressing head is in contact with the end face of the upper end of the metal corrugated pipe blank and is pressed down to be close to the working platform.
5. The hollow inner sleeve hydroforming device according to claim 4, wherein: the outer side end surfaces of the two outer dies are flush with the end surfaces of the upper end and the lower end of the metal corrugated pipe blank, and are respectively attached to the working platform and the working surface of the pressure head; arc transition is performed at the inner diameter corner of the inner side end surfaces of the two outer dies.
6. The hollow inner sleeve hydroforming device according to claim 1, wherein: a bypass overflow valve is arranged on the injection pipe; valves for controlling on-off are arranged on the exhaust pipe and the injection pipe.
7. A forming method using the hollow inner sleeve hydroforming device according to any one of claims 1 to 6, characterized in that: the inner space of the metal corrugated pipe blank is removed through the hollow inner sleeve, so that a sealed space is formed between the inner wall of the metal corrugated pipe blank and the outer wall of the hollow inner sleeve to form an effective area for generating internal pressure, high-pressure water is injected into the sealed space through the injection pipe when the metal corrugated pipe is formed, and the pressure head is axially pushed along the metal corrugated pipe blank until the final shape and size requirements of the metal corrugated pipe are met.
8. The method for forming a hollow inner sleeve hydroforming device according to claim 7, wherein: when the metal corrugated pipe is formed, water is firstly injected into a sealing space between the metal corrugated pipe blank and the hollow inner sleeve through a water injection pipe, and exhaust is carried out through an exhaust pipe; after the sealed space is filled with water, a valve on the exhaust pipe is closed, and then the water injection pipe is pressurized by a high-pressure water pump, when the pressure reaches the initial forming pressure, the high-pressure water injection valve is closed, the hydraulic press is pushed down along the axial direction of the metal corrugated pipe blank by the pressure head, the internal pressure is gradually increased, the bulge of the metal corrugated pipe blank is gradually increased, the pressure in the cavity is controlled to be at the set pressure required by forming by a bypass overflow valve of the water injection pipe, and the redundant water is discharged out of the cavity; the pressure head continues to move downwards for pressurization, and the forming amplitude of the metal corrugated pipe gradually approaches to the finished product state until the design state of the metal corrugated pipe is finally reached.
9. The method for forming a hollow inner sleeve hydroforming device according to claim 8, wherein: when the pressure reaches the initial forming pressure, namely, when the metal corrugated pipe blank starts to bulge at the middle sections of the upper outer die and the lower outer die.
10. The method for forming a hollow inner sleeve hydroforming device according to claim 8, wherein: after the metal corrugated pipe is formed, opening a bypass overflow valve to discharge pressure to zero, discharging water in the cavity, moving the pressure head upwards, sequentially discharging the outer die and the sealing ring, taking out the finished metal corrugated pipe from the workbench, and forming the finished metal corrugated pipe into a single-wave metal corrugated pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311117095.0A CN116967327A (en) | 2023-08-31 | 2023-08-31 | Hydraulic forming device and hydraulic forming method for hollow inner sleeve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311117095.0A CN116967327A (en) | 2023-08-31 | 2023-08-31 | Hydraulic forming device and hydraulic forming method for hollow inner sleeve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116967327A true CN116967327A (en) | 2023-10-31 |
Family
ID=88483319
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311117095.0A Pending CN116967327A (en) | 2023-08-31 | 2023-08-31 | Hydraulic forming device and hydraulic forming method for hollow inner sleeve |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116967327A (en) |
-
2023
- 2023-08-31 CN CN202311117095.0A patent/CN116967327A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6006567A (en) | Apparatus and method for hydroforming | |
| Ahmed et al. | Estimation of machine parameters for hydraulic bulge forming of tubular components | |
| JP3351290B2 (en) | Method and apparatus for hydraulic bulging of metal tube | |
| CN101024236A (en) | Internal high-pressure formation method of special-shape-section pipelike parts | |
| CN107745029A (en) | A kind of store-vessel bottom integral forming method | |
| CN113182388B (en) | Thin-wall multi-cavity member shape correction die and method based on compression deformation | |
| CN112024692B (en) | Ultra-low pressure liquid-filling forming system and method for special-shaped component | |
| EP1100637B1 (en) | Device and method for expansion forming | |
| CN108787845B (en) | Hydraulic forming device for large-diameter thin-wall metal pipe fitting | |
| US6279364B1 (en) | Sealing method and press apparatus | |
| CN220515123U (en) | Hydraulic forming device for hollow inner sleeve | |
| CN116967327A (en) | Hydraulic forming device and hydraulic forming method for hollow inner sleeve | |
| RU2354481C1 (en) | Bellow forming die | |
| KR20040068676A (en) | High Pressure Bellows Forming Device and High Pressure Bellows Forming Method using thereof | |
| CN111112431B (en) | Method for liquid-filled extrusion forming and blade obtained thereby | |
| CN214022876U (en) | Flexible bending forming device for automobile exhaust emission pipe fitting | |
| CN111558645B (en) | Method and device for forming part by conical rubber cylinder | |
| CN203484467U (en) | Manufacturing equipment for large-pipe-diameter titanium corrugated pipe and corrugated pipe | |
| US6089064A (en) | Sliding plug for applying end loads during isostatic bulge forming | |
| RU2118219C1 (en) | Method of forming-drawing articles of sheet material | |
| JP3154630B2 (en) | Container molding method | |
| US6250121B1 (en) | Method for molding metal using high fluid pressure | |
| KR100518994B1 (en) | Hydro compression tube forming die and method for making same | |
| CN214517371U (en) | Pressurizing and upsetting die for variable-section and variable-diameter pipe | |
| CN219561322U (en) | Flange casting forming die |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |