CN110695157A - Method for bending titanium alloy thin-walled tube sharply - Google Patents
Method for bending titanium alloy thin-walled tube sharply Download PDFInfo
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- CN110695157A CN110695157A CN201911003630.3A CN201911003630A CN110695157A CN 110695157 A CN110695157 A CN 110695157A CN 201911003630 A CN201911003630 A CN 201911003630A CN 110695157 A CN110695157 A CN 110695157A
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- 238000005452 bending Methods 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 22
- 229910001069 Ti alloy Inorganic materials 0.000 title claims abstract description 14
- 238000011084 recovery Methods 0.000 claims abstract description 18
- 239000011265 semifinished product Substances 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 8
- 238000009826 distribution Methods 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 230000007547 defect Effects 0.000 abstract description 3
- 238000003825 pressing Methods 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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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
- B21D7/00—Bending rods, profiles, or tubes
- B21D7/06—Bending rods, profiles, or tubes in press brakes or between rams and anvils or abutments; Pliers with forming dies
-
- 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
- B21D3/00—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts
- B21D3/14—Recontouring
-
- 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
- B21D7/00—Bending rods, profiles, or tubes
- B21D7/16—Auxiliary equipment, e.g. for heating or cooling of bends
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Bending Of Plates, Rods, And Pipes (AREA)
Abstract
A method for bending a titanium alloy thin-wall pipe sharply comprises the steps of pressing a round pipe blank to a pipe blank with a nearly elliptical section through a pre-deformation die; bending the tube blank in a bending die; and finally, placing the semi-finished product of the bent pipe in a recovery mould, closing the mould and introducing compressed air to recover the flattened pipe blank into a circular section. The invention can obviously reduce the bending rigidity of the bending part of the pipe, greatly improve the stress-strain state of the round section bent pipe and eliminate the defect; and then placing the bent part in a mould, introducing compressed air, recovering the circular section, and finally obtaining the shape of the sharp-bent pipe fitting.
Description
Technical Field
The invention relates to a technology in the field of material processing, in particular to a method for bending a titanium alloy thin-walled tube sharply.
Background
The pipe is not only used for various pipelines and frame structures, but also made into a complex hollow variable cross-section component, is used for replacing the traditional stamping-welding structural component in the fields of automobiles and aerospace, lightens the structural mass, improves the rigidity and the strength of the structural component, and has wider and wider application range. However, the current pipe bending method has many disadvantages, especially thin-walled pipes, that must be filled with a filler (core rod, core, elastic medium, etc.) to prevent the pipe from buckling and to maintain a circular cross section of the pipe, which results in complicated process equipment. In the conventional bending method, the tensile material on the outer side of the tube blank is elongated by about 140 percent to cause fiber breakage, while the material on the inner side of the tube blank is compressed by about 59 percent to cause instability on the compression side of the fiber to generate folding, and the channel section of the tube blank is also distorted. In the bending process of the pipe, the bending rigidity E.J of the section, namely the product of the elastic modulus E and the inertia moment J of the section plays a key role in the stress-strain state of the pipe during bending, and therefore, the bending rigidity of the pipe can be improved by changing the shape of the section of the bent pipe, namely the stress-strain state of the pipe during bending.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for sharply bending a titanium alloy thin-walled tube, wherein the bending section of a tube blank is pre-flattened and then bent, so that the shape of the bending section of the tube blank is changed, the bending rigidity of the bending part of the tube is obviously reduced, the stress-strain state of the tube with the circular section is greatly improved, and the defect formation is eliminated; and then placing the bent part in a mould, introducing compressed air, recovering the circular section, and finally obtaining the shape of the sharp-bent pipe fitting.
The invention is realized by the following technical scheme:
the invention relates to a sharp bending method of a titanium alloy thin-walled tube, which comprises the steps of pressing a round tube blank to a tube blank with a nearly elliptical section through a pre-deformation die; bending the tube blank in a bending die; and finally, placing the semi-finished product of the bent pipe in a recovery mould, closing the mould and introducing compressed air to recover the flattened pipe blank into a circular section.
The pre-deformation mold comprises: an upper mold half and a lower mold half, wherein: the upper mold half is disposed on and mates with the lower mold half.
The recovery mold comprises: a die, be used for plugging the end cap at blank both ends and resume the terrace die for placing the blank, wherein: 1/2 semicircular grooves are arranged in the female die and the recovery male die.
The inner radius R of the 1/2 semicircular groove is 16mm, the distance from the inner circumference of the groove to the center is 35mm, and the distance from the outer circle to the center is 67 mm.
The step of placing the semi-finished bent pipe in a recovery mould is as follows: and (3) placing the approximately elliptical section of the bent tube blank in a recovery mould, after the mould is closed, sequentially arranging sealing plugs at two ends of the tube blank, and introducing compressed air into the tube blank from one end of the tube blank to recover the circular section or the required section shape of the tube blank.
Technical effects
Because the inertia moment of the pipe blank during bending is greatly reduced (for the pipe blank with the diameter of 30 multiplied by 1.5mm, the inertia moment is about 1/14 of a circular section), the invention greatly optimizes the stress-strain state of the pipe blank during forming, eliminates the common internal and external cracks of the pipe blank during bending, and greatly improves the size precision, the quality and the production efficiency of the bent pipe blank. Meanwhile, the invention simplifies the bending tool, ensures that the bent part has accurate length, and the theory of pre-flattening the bent part of the tube blank is basically consistent with experimental research.
Drawings
FIG. 1 is a schematic view of a deformation process in the examples;
in the figure: a is the original state of the tube blank placed in a flattening die; b is a flattened state; c is a comparison schematic diagram before and after flattening; d is a schematic diagram of calculating the moment of inertia of the cross section of the approximate ellipse part; FIG. 1a, a round section tube blank 1, an upper half die 2, a lower half die 3, FIG. 1b, a tube blank 4 with a near-elliptical section;
FIG. 2 is a schematic view of a bending step of a tube blank in the example;
in fig. 2: a bending die 5 and a bent pipe semi-finished product 6;
FIG. 3 is a schematic view of the tube blank recovery process in the example,
in the figure: the device comprises a sealing plug 7, a recovery convex die 8, a concave die 9, a recovery blank 10 and a guide post 11;
FIG. 4 is a schematic representation of the calculated stress-strain states in the examples;
FIG. 5 is a graphical representation of the die and the geometry of the crushing member in the example;
FIG. 6 is a wall thickness distribution diagram of various shapes of cross sections of the pre-pressing flat pipe along the flow radius of the near-elliptic annular part in the embodiment;
wherein: -is a theoretical curve; ● is the experimental curve;
Detailed Description
In the method for bending a titanium alloy thin-walled tube in a sharp manner, as shown in fig. 1a, a round-section tube blank 1 is a titanium alloy TA16 tube with a diameter of 30 × 1.5mm, and a mold is mounted on an YDZ-D315 hydraulic press, wherein the method comprises the following steps:
1, flattening a blank 1 of a pipe with a circular section shown in a figure 1 into a pipe blank 4 with a nearly elliptical section shown in a B-B section in a figure 1B by a pre-deformation die, wherein the major axis of the blank is 20mm, and the minor axis of the blank is nearly 10 mm;
as shown in fig. 1a and b, the pre-deformation mold comprises: an upper mold half 2, a lower mold half 3, wherein: the upper mold half 2 is placed on and mated with the lower mold half 3.
As shown in fig. 1d, the cross section is a nearly elliptical shape, wherein a is 10 and a1＝8.5、2b＝10、b＝5、b1＝3.5。
and 3, placing the bent pipe semi-finished product 6 with the approximately elliptical section after bending into a recovery mould shown in the figure 3, closing the mould through a press slide block, and introducing compressed air with the pressure of 80MPa for pressure maintaining for 1 minute at normal temperature to recover the original diameter of the flattened pipe blank.
As shown in fig. 3, the recovery mold includes: the female dies 9 are symmetrically arranged for placing blanks, the sealing plugs 7 are arranged at two ends of the bent pipe semi-finished product 6, and the recovery male die 8 is arranged on the bent pipe semi-finished product.
1/2 semicircular grooves are formed in the recovery male die 8 and the female die 9, and the inner radius r of the 1/2 semicircular grooves is 16 mm; the inner circumference of the groove is 35mm from the center, and the outer circumference is 67mm from the center, wherein R-R is 51-16 and R + R is 51+ 16.
As shown in fig. 4, the stress-strain state of the tube blank is determined to satisfy, according to the wall thickness distribution of the part, without considering the contact friction force:
wherein: s is goldThe thickness of the metal flowing at the moment is rho, which is the radius from the metal flowing at the moment to the symmetry axis, sigmasIn order to be a stress for the flow of the material,
a and n are material constants, D is 2 sigmam—σθ+B(2σθ—σm)，σmAnd σθMeridional and circumferential stresses, respectively:
b is the ratio of the stress on the meridian to the stress on the circumference,εnand εθCorresponding to wall thickness and circumferential deformation, ∈iIs the deformation strength.
The original wall thickness S is given according to the integral of a differential equation0Deforming the pre-bent pipe with the thickness of 1.5mm, wherein the hardening index n of the material is 0.2-0.4; from the stress-strain state results, it was determined that the closer the tube blank (bend) is to the mold axis of symmetry, the smaller the part thickness and thickness difference variation obtained in the deformation zone, as shown in fig. 5.
As shown in FIG. 6, the cross sections of the flattened tube with the initial diameter phi of 30mm are distributed theoretically along the flowing radius wall thickness of the part, wherein a curve I corresponds to the cross section of the pre-bent tube at the lower left corner, a curve II corresponds to the cross section of the pre-bent tube at the lower right corner, and a curve III corresponds to the cross section of the pre-bent tube at the upper right corner.
The blank obtained after flattening is shown in FIG. 4 and has a dimension Rc＝35mm，rc＝16～18mm。
As shown in fig. 6, the calculation results substantially coincided with the test results, and the calculation errors of the parameters of deformation and force were not more than 15% and 20%, respectively.
The mold size of this embodiment is: the working surface R is 51mm, 2R is 32mm, R + R is 67mm, R-R is 35 mm. The outer diameter of the long axis of the prepared pre-pressed flat ellipse is 20mm, and the outer diameter of the short axis is nearly 10 mm.
As shown in fig. 1d, the dimensions in the oval cross-section are specifically 2 a-20, a-10, a1＝8.5、2b＝10、b＝5、b13.5, since the bending is symmetrical to the X axis, only the moment of inertia J needs to be calculatedx。
The moment of inertia is multiple after flattening before flattening: J/Jx13673.7/948.07/14.42, wherein 13673.7 is the moment of inertia at the section of the circular ring of the tube blank (the inner and outer diameters are respectively 30mm and D is 27mm) as shown in fig. 1 a.
In conclusion, the method greatly reduces the bending modulus of the pipe blank during bending, the moment of inertia of the oval section after flattening is only about 1/14 of the round section, greatly improves the stress-strain state of the pipe blank during bending, eliminates the outward cracking and inward wrinkling diseases of the traditional pipe blank during bending, reduces the thinning or thickening amount of the pipe blank due to the bending wall thickness, greatly improves the size precision and quality of the bent pipe blank, does not need to fill and charge during bending, and is beneficial to automatic line production.
The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (7)
1. A sharp bending method of a titanium alloy thin-walled tube is characterized in that a round tube blank is pressed to a tube blank with a nearly elliptical section through a pre-deformation die; bending the tube blank in a bending die; and finally, placing the semi-finished product of the bent pipe in a recovery mould, closing the mould and introducing compressed air to recover the flattened pipe blank into a circular section.
2. The method for sharp bending of a titanium alloy thin-walled tube according to claim 1, wherein the pre-deformation mold comprises: an upper mold half and a lower mold half, wherein: placing the tube blank to be flattened into a female die, so that the stress and the strain are greatly improved in the longitudinal bending stage, and the bending rigidity EJ of the section is greatly reduced compared with that of a round section in the bending process, wherein: e is the modulus of elasticity and J is the moment of inertia of the section.
3. The method of claim 1, wherein the recovery mold comprises: a end cap and terrace die for placing the die of blank, being used for shutoff blank both ends, wherein: 1/2 semicircular grooves are arranged in the female die and the male die.
4. The method for sharply bending the titanium alloy thin-walled tube according to claim 1 or 3, wherein the step of placing the semi-finished bent tube in the recovery mold comprises the following steps: and (3) placing the near-elliptical section of the bent tube blank in a recovery mould, and introducing compressed air to recover the original section.
5. The method for sharply bending the titanium alloy thin-walled tube according to claim 3, wherein the stress-strain state of the tube blank is determined by the thickness distribution of the tube blank wall in the female die and the male die to satisfy:
6. The method for bending a titanium alloy thin-walled tube sharply according to claim 3, wherein the 1/2 semicircular grooves have an outer radius R of 51mm and an inner radius R of 16 mm.
7. The method for sharply bending the titanium alloy thin-walled tube according to claim 1, wherein the closing the die and introducing compressed air comprises: and (3) placing the semi-finished product of the bent pipe in a recovery mould, closing the mould through a press slide block, introducing compressed air with the pressure of 80MPa, and maintaining the pressure for 1 minute at normal temperature to recover the original diameter of the flattened pipe blank.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911003630.3A CN110695157B (en) | 2019-10-22 | 2019-10-22 | Method for precisely processing sharp bend of titanium alloy thin-walled tube |
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| CN201911003630.3A CN110695157B (en) | 2019-10-22 | 2019-10-22 | Method for precisely processing sharp bend of titanium alloy thin-walled tube |
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| CN110695157B CN110695157B (en) | 2021-02-09 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112347583A (en) * | 2020-11-08 | 2021-02-09 | 西南石油大学 | Method for calculating limit internal pressure of double-defect-contained bent pipe of booster station |
| CN112548010A (en) * | 2020-11-05 | 2021-03-26 | 宝钛集团有限公司 | Preparation method of titanium and titanium alloy elliptical ring material |
| CN113319150A (en) * | 2021-06-03 | 2021-08-31 | 哈尔滨工业大学 | Size correction method for elbow passing pipe fitting |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB680411A (en) * | 1950-03-09 | 1952-10-01 | Andre Huet | Method of shaping hollow metal bodies |
| CN201552240U (en) * | 2009-12-01 | 2010-08-18 | 无锡市新峰管业有限公司 | Forming mould of elbow pipe |
| CN101823085A (en) * | 2009-03-04 | 2010-09-08 | 西北工业大学 | Variable-channel extrusion die and forming method |
| CN104128398A (en) * | 2014-06-20 | 2014-11-05 | 武汉华液传动制造有限公司 | Numerical control push type pipe bending machine and bending method thereof |
| CN105855344A (en) * | 2015-01-21 | 2016-08-17 | 保隆(安徽)汽车配件有限公司 | Forming method for small-radius bent pipes |
-
2019
- 2019-10-22 CN CN201911003630.3A patent/CN110695157B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB680411A (en) * | 1950-03-09 | 1952-10-01 | Andre Huet | Method of shaping hollow metal bodies |
| CN101823085A (en) * | 2009-03-04 | 2010-09-08 | 西北工业大学 | Variable-channel extrusion die and forming method |
| CN201552240U (en) * | 2009-12-01 | 2010-08-18 | 无锡市新峰管业有限公司 | Forming mould of elbow pipe |
| CN104128398A (en) * | 2014-06-20 | 2014-11-05 | 武汉华液传动制造有限公司 | Numerical control push type pipe bending machine and bending method thereof |
| CN105855344A (en) * | 2015-01-21 | 2016-08-17 | 保隆(安徽)汽车配件有限公司 | Forming method for small-radius bent pipes |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112548010A (en) * | 2020-11-05 | 2021-03-26 | 宝钛集团有限公司 | Preparation method of titanium and titanium alloy elliptical ring material |
| CN112548010B (en) * | 2020-11-05 | 2024-04-09 | 宝钛集团有限公司 | Preparation method of titanium alloy elliptical ring material |
| CN112347583A (en) * | 2020-11-08 | 2021-02-09 | 西南石油大学 | Method for calculating limit internal pressure of double-defect-contained bent pipe of booster station |
| CN112347583B (en) * | 2020-11-08 | 2022-01-28 | 西南石油大学 | Method for calculating limit internal pressure of double-defect-contained bent pipe of booster station |
| CN113319150A (en) * | 2021-06-03 | 2021-08-31 | 哈尔滨工业大学 | Size correction method for elbow passing pipe fitting |
| CN113319150B (en) * | 2021-06-03 | 2022-07-01 | 哈尔滨工业大学 | Size correction method for elbow passing pipe fitting |
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Denomination of invention: Precision machining method for rapid bending of titanium alloy thin-walled pipes Effective date of registration: 20231106 Granted publication date: 20210209 Pledgee: Meixi Branch of Zhejiang Anji Rural Commercial Bank Co.,Ltd. Pledgor: ZHEJIANG SHENJI TITANIUM INDUSTRY Co.,Ltd. Registration number: Y2023330002528 |
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