CN109622698B - Device and method for preparing steel pipes with alternately distributed strength - Google Patents
Device and method for preparing steel pipes with alternately distributed strength Download PDFInfo
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- CN109622698B CN109622698B CN201811488112.0A CN201811488112A CN109622698B CN 109622698 B CN109622698 B CN 109622698B CN 201811488112 A CN201811488112 A CN 201811488112A CN 109622698 B CN109622698 B CN 109622698B
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- 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
- B21D15/04—Corrugating tubes transversely, e.g. helically
- B21D15/10—Corrugating tubes transversely, e.g. helically by applying fluid pressure
Abstract
The invention belongs to the field of hydraulic forming, and particularly relates to a device and a method for preparing steel pipes with alternately distributed strength. The device comprises an upper die, a lower die, a top block, a pressure head, a hydraulic pump, a hydraulic pipe and a fixed block body; the pressure head is provided with a plurality of small pressure heads, and a plurality of grooves are uniformly arranged on the inner peripheral surfaces of the upper die and the lower die at intervals; a hydraulic hole is correspondingly arranged at the position of each groove of the upper die, and the small pressure heads are respectively arranged in the corresponding hydraulic holes; a first cavity is formed inside the steel pipe blocked by the top block, a second cavity is formed on the pipe wall of the steel pipe and the surface of the annular groove, and hydraulic oil is injected into the second cavity; the hydraulic pump and the hydraulic pipe provide bulging pressure for the first chamber, and the pressure head provides reverse bulging pressure for the second chamber. According to the invention, the steel pipe is subjected to local repeated bulging and reverse bulging to generate strain induced martensite phase transformation, so that the martensite content of the bulging and reverse bulging part is increased, and the steel pipe is in a lamellar structure with alternately strong and weak distribution in the axial direction, so that the steel pipe with alternately strong and weak distribution is prepared.
Description
Technical Field
The invention belongs to the field of hydraulic forming, and particularly relates to a device and a method for preparing steel pipes with alternately distributed strength.
Background
Stainless steel materials contain a variety of textures, such as face-centered cubic austenite and body-centered cubic martensite. A large number of documents show that the martensitic transformation has a great influence on the mechanical properties of stainless steel materials. Transformation Induced Plasticity (TRIP) is the strain-Induced martensitic Transformation that occurs when a material is subjected to an external force or a thermal load. The hard martensite phase resulting from the transformation and the mechanical incompatibility between the soft and hard phases may provide a very high strain hardening rate. Therefore, by plastically deforming austenitic stainless steel and inducing strain-induced martensitic transformation, the strain hardening rate of the material can be increased, and the strength and tensile plasticity of the stainless steel can be increased.
The stainless steel pipe manufactured by the traditional process has single structural performance and cannot meet the requirements of certain special performance, for example, at the corner of a pipeline, the pipe is ensured to have better plasticity so as to be convenient for forming a bent pipe, the pipe is ensured to have enough strength to bear the impact of liquid in the pipeline, and the traditional pipe is a homogeneous material and cannot meet the requirements of good plasticity and larger strength at the same time.
Disclosure of Invention
The invention aims to provide a device and a method for preparing steel pipes with alternately distributed strength.
The technical solution for realizing the purpose of the invention is as follows:
a device for preparing steel pipes with alternately distributed strength comprises an upper die, a lower die, a top block, a pressure head, a hydraulic pump, a hydraulic pipe and a fixed block body; the pressing head is provided with a plurality of small pressing heads, a plurality of grooves are uniformly arranged on the inner peripheral surfaces of the upper die and the lower die at intervals, the number of the grooves is the same as that of the small pressing heads, and after die assembly is carried out, the grooves of the upper die and the grooves of the lower die form a complete annular groove; a hydraulic hole is correspondingly arranged at the position of each groove of the upper die, and small pressure heads of the pressure heads are respectively arranged in the corresponding hydraulic holes;
the steel pipe is positioned in a cavity formed after the upper die and the lower die are closed, and the top block is used for sealing two ends of the steel pipe; a first cavity is formed inside the steel pipe blocked by the top block, a second cavity is formed on the pipe wall of the steel pipe and the surfaces of the annular grooves of the upper die and the lower die, and hydraulic oil is injected into the second cavity; the hydraulic pump and the hydraulic pipe provide bulging pressure for the first chamber, and the pressure head provides reverse bulging pressure for the second chamber.
And sealing rings are arranged at two ends of the steel pipe and between the upper die and the lower die.
And a sealing ring is arranged between the pressure head and the through hole of the upper die.
A method for preparing steel pipes with alternately distributed strength and weakness by using the preparation device is characterized in that the steel pipes are made of a material with strain-induced phase change, and the method specifically comprises the following steps:
the method comprises the following steps: installing a mould;
step two: and (3) bulging: the hydraulic pumps on the two sides are started to provide hydraulic pressure for the first cavity, the steel pipe is stably expanded under the action of the hydraulic pressure to form the steel pipe with a plurality of annular bulges, and the steel pipe on the expanded part undergoes the first martensite phase change;
step three: and (3) reverse bulging: the hydraulic pumps on the two sides reduce pressure, the pressure head performs reverse bulging on the steel pipe with the plurality of annular bulges under the action of the press machine, so that the steel pipe returns to the state of the steel pipe which is not deformed, and the reverse bulging part generates second martensite phase transformation;
step four: and repeating the second step and the third step, wherein martensite phase transformation is accumulated in the bulging part, so that the martensite of the bulging part is gradually increased, the strength is gradually improved, and the steel pipe is in a lamellar structure with alternately strong and weak distribution in the axial direction.
The steel pipe is 304 stainless steel, 306 stainless steel or 316 stainless steel.
The first step is specifically as follows: installing a sealing ring in a die cavity formed by an upper die and a lower die, placing a steel pipe in an original state, placing ejector blocks at two ends of the die cavity, fixing fixed block bodies at two sides of the upper die and the lower die, connecting a hydraulic pump and the die through a hydraulic pipe, filling hydraulic oil into a hydraulic hole of the upper die, installing a pressure head, and placing the device on a press machine.
The second step further comprises: the pressure head presses 1/10 of total allowable stroke under the action of the press machine, and back pressure is provided for smooth expansion.
And during the bulging in the second step, the hydraulic pressure in the first cavity is 350-450 MPa.
And during the reverse bulging in the third step, the hydraulic pressure in the first cavity is reduced to 150-250 MPa.
Compared with the prior art, the invention has the following remarkable advantages:
(1) the invention adopts the hydraulic forming technology, and the steel pipe is locally and repeatedly expanded and reversely expanded to generate strain induced martensite phase transformation, so that the martensite content of the expanded and reversely expanded part is increased, the strength is increased, and the steel pipe is in a lamellar structure with alternately strong and weak distribution in the axial direction to prepare the steel pipe with alternately strong and weak distribution.
(2) The invention adopts a hydraulic repeated bulging method to prepare the novel steel pipes with alternately distributed strengths, has great design directivity and flexibility in structural design, can reasonably adjust the bulging times according to requirements, and prepares the novel steel pipes with alternately distributed strengths with different strength requirements.
(3) The invention presents the alternate distribution of soft phase and hard phase in the axial direction of the steel pipe, so that the prepared novel steel pipe with alternate distribution of strong phase and weak phase can have the toughness of the soft phase and the strength of the hard phase at a certain degree, and can meet the application requirements of some special industries.
(4) The steel pipe jacking device is simple in structure, and can select a proper jacking block according to the change of the length of the steel pipe, so that the preparation of steel pipes with various lengths and distributed at intervals is realized.
The present invention is described in further detail below with reference to the attached drawing figures.
Drawings
FIG. 1 is a schematic view of a steel pipe manufacturing apparatus according to the present invention.
FIG. 2 is a sectional view of the manufacturing apparatus with the steel pipe in its original form.
FIG. 3 is a sectional view of the manufacturing apparatus after the steel pipe is expanded.
FIG. 4 is a schematic diagram of the bulging and reverse bulging of a steel pipe.
FIG. 5 is a schematic axial sectional view of a steel pipe, wherein (a) is a schematic sectional view of a steel pipe before deformation and (b) is a schematic sectional view of a steel pipe after bulging.
Description of the reference numerals
1-pressure head, 2-upper die, 3-fixed block, 4-top block, 5-lower die, 6-1-original state steel pipe, 6-2-bulging state steel pipe, 7-bolt, 8-hydraulic pipe, 9-sealing ring, 10-hydraulic hole and 11-hydraulic pump.
Detailed Description
As shown in fig. 1-2, the hydroforming apparatus of the present invention comprises: the device comprises a pressure head 1, an upper die 2, a lower die 5, a fixed block 3, a top block 4, a hydraulic pump 11 and the like; the hydraulic pumps 11 at two sides control the bulging of the steel pipe, the pressure head 1 at the top part carries out reverse bulging on the bulged steel pipe under the action of the press machine, so that the steel pipe is restored to the original state, and the schematic diagrams of bulging and reverse bulging are shown in fig. 4.
The invention is realized by the following technical scheme, which comprises the following steps:
the method comprises the following steps: mounting the device, namely mounting a sealing ring 9 into a mold cavity formed by an upper mold 2 and a lower mold 5; putting the steel pipe in an original state; putting top blocks at two ends of a mold cavity; fixing the fixing block 3 on two sides of the upper die 2 and the lower die 5 by bolts; connecting a hydraulic pump 11 with the die through a hydraulic pipe 8; the hydraulic oil is filled into the hydraulic hole of the upper die 2, the press head is installed, the device is placed on the press, and the steel pipe 6-1 in the original state and the installed device are shown in the figure 1.
Step two: bulging, namely, a pressure head 1 presses down a small amount of stroke under the action of a press machine to provide a small amount of back pressure for smooth bulging; the hydraulic pumps 11 on the two sides are started, the steel pipe is stably expanded under the action of hydraulic pressure, the metal of the expanded part generates the first martensitic transformation due to the strain, and the expanded steel pipe 6-2 and the device are shown in figure 3.
Step three: and (3) reverse bulging: the hydraulic pumps 11 on the two sides reduce the pressure of the inner cavity, the pressure head 1 carries out reverse bulging on the bulging steel pipe under the action of the press machine, the bulging steel pipe is made to return to the original steel pipe state, and the metal strain of the bulging part generates second martensite phase transformation.
Step four: repeating the second step and the third step, wherein martensite phase transformation is accumulated in the bulging part, so that the martensite of the bulging part is gradually increased, the strength is gradually improved, and the steel pipe is in a lamellar structure with alternately strong and weak distribution in the axial direction; according to the requirement of the service condition of the steel pipe, the proper bulging times can be selected, and the preparation of the steel pipes with different performances and use requirements can be realized.
Example 1
Taking 304 stainless steel as an example, the following example relates to a three-step process, and gives detailed embodiments and specific operations: installation, bulging and the anti-bulging of mould, wherein:
the method comprises the following steps: installing a mould, namely installing a sealing ring 9 into a mould cavity formed by an upper mould 2 and a lower mould 5 as shown in figure 2; putting a 304 stainless steel pipe; putting the top blocks 4 at two ends of the mold cavity; fixing the fixed block 3 on two sides of the upper die 2 and the lower die 5 by bolts 7; connecting a hydraulic pump 11 with the die through a hydraulic pipe 8; the hydraulic oil is filled into the hydraulic hole 10 of the upper die, the pressure head 1 is installed, and the device is placed on a press machine.
Step two: in the bulging process, the pressure head 1 presses 1/10 of total allowable stroke under the action of a press machine, so that a small amount of back pressure is provided for smooth bulging; the hydraulic pumps 11 on both sides are turned on to provide hydraulic pressure of about 400Mpa to the interior of the hydraulic chamber, the 304 steel pipe is stably expanded under the action of the hydraulic pressure, and the 304 steel pipe in the expanded portion undergoes a first martensitic transformation in response to the deformation, as shown in fig. 3.
Step three: and in the reverse bulging process, the hydraulic pumps 11 on the two sides are decompressed to 200Mpa, the pressure head 1 performs reverse bulging on the bulged 304 steel pipe under the action of the press machine, so that the bulged 304 steel pipe is restored to the state of the undeformed 304 steel pipe, and the metal strain of the bulged part generates secondary martensite phase transformation.
Step four: repeating the bulging and reverse bulging processes twice, so that the martensite of the bulging part in the 304 steel pipe is gradually increased, the local strength of the 304 steel pipe is gradually improved, and the steel pipe is in a lamellar structure with strength distributed alternately in the axial direction; the axial sectional view of the steel pipe after working and the composition of the unformed steel pipe are shown in FIG. 5.
Claims (9)
1. The device for preparing the steel pipes with the strength distributed alternately is characterized by comprising an upper die (2), a lower die (5), a top block (4), a pressure head (1), a hydraulic pump (11), a hydraulic pipe (8) and a fixed block body (3); a plurality of small pressure heads are arranged on the pressure head (1), a plurality of grooves are uniformly arranged on the inner peripheral surfaces of the upper die (2) and the lower die (5) at intervals, the number of the grooves is the same as that of the small pressure heads, and after die assembly is carried out, the grooves of the upper die (2) and the grooves of the lower die (5) form a complete annular groove; a hydraulic hole is correspondingly arranged at the position of each groove of the upper die (2), and small pressure heads of the pressure head (1) are respectively arranged in the corresponding hydraulic holes;
the steel pipe is positioned in a cavity formed after the upper die (2) and the lower die (5) are closed, and the top block (4) is used for sealing two ends of the steel pipe; a first cavity is formed in the steel pipe blocked by the top block (4), a second cavity is formed on the pipe wall of the steel pipe and the surfaces of the annular grooves of the upper die (2) and the lower die (5), and hydraulic oil is injected into the second cavity; the hydraulic pump (11) and the hydraulic pipe (8) provide bulging pressure for the first chamber, and the pressure head (1) provides reverse bulging pressure for the second chamber.
2. The manufacturing device according to claim 1, wherein a seal ring (9) is arranged between the two ends of the steel pipe and the upper die (2) and the lower die (5).
3. The device according to claim 1, characterized in that a sealing ring is arranged between the ram (1) and the hydraulic bore of the upper die (2).
4. A method for preparing steel pipes with strength distributed at intervals by using the preparation device of any one of claims 1 to 3, wherein the steel pipes are made of a material with strain-induced phase change, and the method specifically comprises the following steps:
the method comprises the following steps: installing a mould;
step two: and (3) bulging: the hydraulic pumps (11) on the two sides are started to provide hydraulic pressure for the first cavity, the steel pipe is stably expanded under the action of the hydraulic pressure to form the steel pipe with a plurality of annular bulges, and the steel pipe on the expanded part undergoes the first martensite phase transformation;
step three: and (3) reverse bulging: the hydraulic pumps (11) on the two sides are decompressed, the pressure head (1) carries out reverse bulging on the steel pipe with the plurality of annular bulges formed in the step two under the action of the press machine, so that the steel pipe is restored to an undeformed steel pipe state, and the reverse bulging part generates a second martensitic phase change;
step four: and repeating the second step and the third step, wherein martensite phase transformation is accumulated in the bulging part, so that the martensite of the bulging part is gradually increased, the strength is gradually improved, and the steel pipe is in a lamellar structure with alternately strong and weak distribution in the axial direction.
5. The method of claim 4, wherein the steel tube is 304 stainless steel, 306 stainless steel, or 316 stainless steel.
6. The method according to claim 4, wherein the first step is specifically: installing a sealing ring (9) into a die cavity formed by an upper die (2) and a lower die (5), placing a steel pipe in an original state, placing ejector blocks (4) at two ends of the die cavity, fixing block bodies (3) at two sides of the upper die (2) and the lower die (5), connecting a hydraulic pump (11) with the die through a hydraulic pipe (8), filling hydraulic oil into a hydraulic hole of the upper die (2), installing a pressure head (1), and placing the device on a press machine.
7. The method of claim 4, wherein the second step further comprises: the pressure head (1) presses 1/10 of total allowable stroke under the action of the press machine to provide back pressure for smooth expansion.
8. The method as claimed in claim 4, wherein the hydraulic pressure in the first chamber during the expanding in the second step is 350-450 MPa.
9. The method as claimed in claim 8, wherein the hydraulic pressure in the first chamber is reduced to 150-250Mpa during the step three reverse bulging.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811488112.0A CN109622698B (en) | 2018-12-06 | 2018-12-06 | Device and method for preparing steel pipes with alternately distributed strength |
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| CN201811488112.0A CN109622698B (en) | 2018-12-06 | 2018-12-06 | Device and method for preparing steel pipes with alternately distributed strength |
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| CN109622698A CN109622698A (en) | 2019-04-16 |
| CN109622698B true CN109622698B (en) | 2020-04-07 |
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| CN111390005B (en) * | 2020-03-24 | 2021-01-29 | 燕山大学 | Thin-wall straight pipe strengthening device and strengthening method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10277660A (en) * | 1997-04-11 | 1998-10-20 | Hitachi Ltd | Method and device for hydrostatic forming, manufacture of bellows, and tubular structure |
| DE19751035A1 (en) * | 1997-11-18 | 1999-05-27 | Forschungsges Umformtechnik | Method and press tool for hydraulically forming items from sheet or tube |
| JP2005296969A (en) * | 2004-04-07 | 2005-10-27 | Nippon Steel Corp | Hydroforming method |
| CN101172292A (en) * | 2006-10-30 | 2008-05-07 | 通用汽车环球科技运作公司 | Hydroformed tubular members and method of hydroforming tubular members for vehicles |
| CN102133596A (en) * | 2010-01-27 | 2011-07-27 | 宁波市华涛不锈钢管材有限公司 | Inside high-pressure molding method and device of thin-wall stainless steel tube |
| CN108326107A (en) * | 2017-12-31 | 2018-07-27 | 潍坊倍力汽车零部件有限公司 | Without liquid-filled shape tube hydraulic forming method and device |
-
2018
- 2018-12-06 CN CN201811488112.0A patent/CN109622698B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10277660A (en) * | 1997-04-11 | 1998-10-20 | Hitachi Ltd | Method and device for hydrostatic forming, manufacture of bellows, and tubular structure |
| DE19751035A1 (en) * | 1997-11-18 | 1999-05-27 | Forschungsges Umformtechnik | Method and press tool for hydraulically forming items from sheet or tube |
| JP2005296969A (en) * | 2004-04-07 | 2005-10-27 | Nippon Steel Corp | Hydroforming method |
| CN101172292A (en) * | 2006-10-30 | 2008-05-07 | 通用汽车环球科技运作公司 | Hydroformed tubular members and method of hydroforming tubular members for vehicles |
| CN102133596A (en) * | 2010-01-27 | 2011-07-27 | 宁波市华涛不锈钢管材有限公司 | Inside high-pressure molding method and device of thin-wall stainless steel tube |
| CN108326107A (en) * | 2017-12-31 | 2018-07-27 | 潍坊倍力汽车零部件有限公司 | Without liquid-filled shape tube hydraulic forming method and device |
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