CN117634238A - Manufacturing method for preventing buckling failure of internal pressure thin-wall steel dished end socket - Google Patents
Manufacturing method for preventing buckling failure of internal pressure thin-wall steel dished end socket Download PDFInfo
- Publication number
- CN117634238A CN117634238A CN202311521143.2A CN202311521143A CN117634238A CN 117634238 A CN117634238 A CN 117634238A CN 202311521143 A CN202311521143 A CN 202311521143A CN 117634238 A CN117634238 A CN 117634238A
- Authority
- CN
- China
- Prior art keywords
- seal head
- pressure
- head
- buckling
- manufacturing
- 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
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 41
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 15
- 239000010959 steel Substances 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 claims abstract description 49
- 239000000463 material Substances 0.000 claims abstract description 31
- 238000004364 calculation method Methods 0.000 claims abstract description 24
- 238000007789 sealing Methods 0.000 claims abstract description 18
- 238000013461 design Methods 0.000 claims abstract description 9
- 230000007704 transition Effects 0.000 claims description 11
- 238000009987 spinning Methods 0.000 claims description 10
- 229910000851 Alloy steel Inorganic materials 0.000 claims description 4
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 2
- 239000010962 carbon steel Substances 0.000 claims description 2
- 238000012360 testing method Methods 0.000 abstract description 19
- 238000004458 analytical method Methods 0.000 abstract description 3
- 238000012937 correction Methods 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 238000005482 strain hardening Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- 238000004088 simulation Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 235000013405 beer Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
Landscapes
- Pressure Vessels And Lids Thereof (AREA)
Abstract
The invention relates to the field of pressure vessel manufacturing, and aims to provide a manufacturing method for preventing buckling failure of an internal pressure thin-wall steel dished end socket. Comprising the following steps: preliminarily confirming the size, the material and the numerical value of the manufacturing process of the dish-shaped sealing head according to the design requirement of the pressure vessel; calculating buckling pressure of the inner pressure steel dished end socket according to a specific buckling pressure calculation formula, and adjusting the size or the material of the end socket if the buckling pressure is smaller than the internal pressure born by the end socket under the process condition of the design requirement; repeating the calculation step until the buckling pressure obtained by calculation is larger than the internal pressure born by the seal head under the process condition; and manufacturing the dish-shaped seal head according to the conventional operation flow according to the finally used seal head parameters and the selected manufacturing process. The buckling pressure calculation formula used in the invention is based on an elastoplastic finite element method, and is obtained by carrying out engineering test result analysis, test correction and safety margin redundancy after a series of influence factors are considered, so that the accuracy and the safety of design and manufacture can be ensured.
Description
Technical Field
The invention relates to the field of pressure vessel manufacturing, in particular to a manufacturing method for preventing buckling failure of an internal pressure thin-wall steel dished end socket.
Background
The dish-shaped seal head is a seal head type commonly used for a pressure container, and the structure of the seal head comprises a straight edge section, a transition area and a spherical crown area, and is widely applied to industries such as petrochemical industry, nuclear power, food processing and the like. Such as coke drums, containment vessels for nuclear power plants, beer fermenters, etc., typically employ thin-walled dished heads (typically with a aspect ratio D i The end enclosure with the t being more than or equal to 100 is called a thin-wall end enclosure). However, the transition region is subjected to circumferential compressive stress under the action of internal pressure, so that the thin-wall dished seal head is easy to generate buckling failure and loses structural stability. Therefore, buckling failure is an important failure mode which needs to be prevented when the internal pressure thin-wall dished seal head is designed.
In order to prevent buckling failure of the inner pressure dished end socket, a buckling pressure prediction formula of the inner pressure dished end socket needs to be established. At present, the formulas for predicting the buckling pressure of the inner pressure steel disc-shaped sealing head mainly comprise an Ayleard & galleltly formula, a galleltly & Radhamohan formula, a galleltly & Blachut formula and a Miller formula.
(1) Ayleward & Galletly formula
Aylward&Gallity adopts BOSOR4 software to develop parametric study of the elastic buckling pressure of the dish-shaped end socket, and fits an elastic buckling pressure calculation formula of the dish-shaped end socket, but the formula is not suitable for the diameter-thickness ratio D i /t<500. The research shows that the internal pressure buckling of the steel dished seal head with the common size for engineering belongs to plastic buckling after the material enters a plastic region, so that the elastic buckling pressure calculation formula gives out an excessively high predicted value, and the prediction accuracy is poor.
(2) Gallitly & Radhamohan formula
Galletly&The influence of geometric parameters and material performance parameters on the plastic buckling pressure of the internal pressure dished end socket is researched by using a BOSOR5 program by Radhamohan, and a formula for predicting the plastic buckling pressure of the dished end socket is provided according to the research result of the parameters. But the formula is not applicable to the aspect ratio D i /t<500 and D i /t>1500. Furthermore, the formula is based on ideal plasticity theory, without considering that the material should hardenStrengthening effect on buckling pressure of the sealing head is achieved.
(3) Galletly formula
Galletly uses BOSOR5 software to compare R i /D i Parameterized study was performed on dished head buckling pressure=1.0, and a dished head buckling pressure calculation formula was obtained by curve fitting. But the formula is only applicable to R i /D i Disc-shaped closure head=1.0, and is not applicable to D i /t<500 and D i /t>1250, the application scope is small. The formula is established based on an ideal plasticity theory, and the strengthening effect of material strain hardening on the buckling pressure of the end socket is not considered.
(4) Galletly & Blachut formula
Galletly&Blachut expands the parameterized analysis range of the seal head size, and fits two internal pressure dished seal head buckling pressure calculation formulas. But the formula is not applicable to the aspect ratio D i /t>1500, and the formula is established based on an ideal plasticity theory, and the strengthening effect of material strain hardening on the buckling pressure of the seal head is not considered.
(5) Miller formula
The Miller determines theoretical calculation formulas of dish-shaped seal head yield pressure and elastic buckling critical pressure based on a thin shell theory and an elastic buckling theory, and reduces the theoretical calculation formulas by adopting a lower envelope curve method through test data, thereby providing an internal pressure dish-shaped seal head buckling pressure calculation formula. The formula is established based on a lower envelope curve method, the buckling pressure predicted value is lower than the test result, and the prediction accuracy is lower. In addition, the formula is complex in form and complex in calculation.
Based on the above, the manufacturing method for preventing buckling failure of the internal pressure thin-wall steel dished end socket is practically significant for production and application.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects in the prior art and providing a manufacturing method for preventing buckling failure of an internal pressure thin-wall steel dished end socket.
In order to solve the problems, the solution of the invention is as follows:
the manufacturing method for preventing buckling failure of the internal pressure thin-wall steel dished end socket comprises the following steps:
(1) According to the design requirement of the pressure vessel, the size, the material and the numerical value of the manufacturing process of the dish-shaped sealing head are preliminarily confirmed, and the method comprises the following steps: inner diameter D of seal head i Radius R of spherical cap region i Radius of transition region r, head thickness t, and material yield strength S y ；
(2) The buckling pressure of the inner pressure steel dished end socket is calculated according to the following formula:
wherein: p (P) b Buckling pressure of the dish-shaped seal head is expressed in MPa; coefficient beta t In connection with the manufacturing process, for spinning and stamping closure heads beta t =1.0 for split head β t ＝0.8；S y The yield strength of the material used for the seal head is expressed in MPa; t is the thickness of the dish-shaped seal head, and the unit is mm; d (D) i The inner diameter of the dish-shaped seal head is in mm; r is R i The radius of the spherical crown area is in mm; r is the radius of the transition zone, and the unit is mm;
(3) If the buckling pressure P of the obtained sealing head is calculated b The internal pressure of the seal head is smaller than the internal pressure of the seal head under the process condition required by design, and after the size or the material of the seal head is required to be adjusted, the calculation is carried out again according to the formula in the step (2);
(4) Repeating the step (3) until the buckling pressure P is calculated b The internal pressure of the seal head is larger than that of the seal head under the process condition;
(5) And (3) manufacturing the dish-shaped seal head according to the seal head parameters used in the final determination of the calculation result in the step (4) and the selected manufacturing process and the conventional operation flow.
As a preferable scheme of the invention, the diameter-thickness ratio D of the dish-shaped seal head is ensured when the size of the seal head is adjusted i The/t satisfies: d is not less than 20 i /t≤2000。
As a preferable scheme of the invention, the size of the sealing head is adjustedAt the whole time, the ratio R of the radius of the spherical crown area of the dish-shaped end socket to the inner diameter of the end socket is ensured i /D i The method meets the following conditions: r is more than or equal to 0.7 i /D i ≤1。
As a preferable scheme of the invention, when the size of the seal head is adjusted, the ratio r/D of the radius of the transition area of the dish-shaped seal head to the inner diameter of the seal head is ensured i The method meets the following conditions: r/D is 0.06.ltoreq.r/D i ≤0.2。
As a preferred embodiment of the present invention, the material of the dish-shaped closure head is carbon steel, low alloy steel or high alloy steel conforming to the pressure vessel manufacturing standard.
As a preferred scheme of the invention, the conventional process for manufacturing the dish-shaped seal head specifically refers to the process of manufacturing the seal head by adopting a stamping process, a spinning process or a split forming process.
As a preferred scheme of the invention, the inner diameter D of the dish-shaped sealing head i And when the grain size is more than or equal to 4 meters, processing and manufacturing are carried out by adopting a split forming process.
In general, the diameter of the seal head processed by the stamping process is 3-4 m at maximum, and if the diameter is larger, a split forming process is needed. The stamping and spinning processes are not usually distinguished by the diameters of the sealing heads, but spinning processing can be adopted for sealing heads smaller than 3m, and the spinning pressure is stronger than stamping in practical application, so that larger sealing heads can be processed.
Description of the inventive principles:
in order to solve the technical problems, a research team of the applicant establishes a dish-shaped seal head internal pressure buckling prediction model considering the influence of material strain hardening based on an elastoplastic finite element method; and the influence rule of the geometric dimension of the dish-shaped end socket and the material yield strength on the internal pressure buckling is ascertained by utilizing the dish-shaped end socket internal pressure buckling prediction model. According to the internal pressure buckling influence factors, considering different material strengths and geometric parameters, carrying out parameterized numerical calculation by utilizing a buckling prediction model, and fitting a brand-new dish-shaped seal head buckling pressure calculation method based on calculation results; and on the basis, a series of industrial scale dish-shaped seal head internal pressure buckling tests with different sizes, materials and manufacturing processes are further combined, and the fitted dish-shaped seal head internal pressure buckling pressure calculation formula is subjected to test correction, so that the buckling pressure calculation formula provided by the invention is finally obtained.
The method of the invention is obtained according to a series of engineering test result analysis, test correction and safety margin redundancy, and further obtains the diameter-thickness ratio D of the dish-shaped sealing head for ensuring the accuracy and the safety of design and manufacture i T, ratio R of spherical crown area radius to head inner diameter i /D i And the ratio r/D of the radius of the transition zone to the inner diameter of the end socket i The requirements are put forward.
Compared with the prior art, the method has the beneficial effects that:
1. on the basis of a large number of experimental researches and mass data simulation, the method establishes a formula for calculating the buckling pressure after ascertaining the buckling pressure influence factors and summarizing the influence rules. The Miller formula calculates the buckling pressure according to more than ten formulas; compared with Miller formulas, the calculation method is simple in form and convenient to calculate.
2. Because the formula is obtained based on mass numerical simulation and end socket test data results and covers a wider range of dish-shaped end socket dimension parameters, compared with the Aylward & galleltly formula, the galleltly & Radhamohan formula, the galleltly formula and the galleltly & Blachut formula, the calculated formula is wide in application range and particularly suitable for dish-shaped end sockets with smaller diameter-thickness ratio.
3. The calculation formula of the buckling pressure of the internal pressure dished head is based on the elastoplastics theory, considers the strain hardening effect of the material, and is corrected by the industrial scale dished head test data, and the prediction accuracy is higher than that of the existing formula.
Drawings
FIG. 1 is a schematic cross-sectional view of a dished closure head.
Detailed Description
The following describes an embodiment of the present invention in detail, and the structural dimensions of the dished closure are shown in fig. 1.
Specific application example one:
(1) The process conditions require that the internal pressure born by the seal head is 1.0MPa, and the size of the dish-shaped seal head is preliminarily selected: inner diameter D i ＝4797mm，D i /t＝872，R i /D i ＝0.78，r/D i =0.21; the end socket material is SA738 Gr.B, and the yield strength S of the material is obtained through a pre-performed tensile test y =588 MPa, split-forming fabrication process is selected;
(2) The buckling pressure of the inner pressure steel dished end socket is calculated according to the following formula:
wherein: p (P) b Buckling pressure of the dish-shaped seal head is expressed in MPa; t is the thickness of the dish-shaped seal head, and the unit is mm; d (D) i The inner diameter of the dish-shaped seal head is in mm; r is R i The radius of the spherical crown area is in mm; r is the radius of the transition zone, and the unit is mm; s is S y The yield strength of the material used for the seal head is expressed in MPa; for split-forming manufacturing processes, beta t ＝0.8；
(3) Calculating to obtain buckling pressure P of the dish-shaped seal head b =1.17 MPa, which is greater than 1.0MPa of internal pressure to which the head is subjected (under the process conditions of the vessel application scenario) required by the pressure design;
(4) And (3) manufacturing the dish-shaped sealing head according to the conventional operation flow of split forming according to the size, the material and the manufacturing process determined in the step (1). The closure was subjected to an internal pressure buckling test by the method described in reference (Pressure Testing of Large-Scale Torispherical Heads Subjected to Knuckle buckling.Miller C D, grove R B, bennett J G.INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING,1986, 22:147-159) to give a buckling pressure test value of 1.15MPa, which is greater than the pressure required for the process conditions by 1.0MPa. Therefore, in the embodiment, the dished seal head manufactured by the method of the invention cannot generate buckling failure.
Specific application example II:
(1) The process conditions require that the internal pressure born by the seal head is 1.8MPa, and the size of the dish-shaped seal head is preliminarily selected: inner diameter D i ＝1800mm，D i /t＝450，R i /D i ＝1.01，r/D i =0.12; the end socket material is S30508, and is pulled in advanceYield strength S of the material obtained by elongation test y =392 MPa, selecting a spin-on manufacturing process;
(2) The buckling pressure of the inner pressure steel dished end socket is calculated according to the following formula:
wherein: p (P) b Buckling pressure of the dish-shaped seal head is expressed in MPa; t is the thickness of the dish-shaped seal head, and the unit is mm; d (D) i The inner diameter of the dish-shaped seal head is in mm; r is R i The radius of the spherical crown area is in mm; r is the radius of the transition zone, and the unit is mm; s is S y The yield strength of the material used for the seal head is expressed in MPa; for the spinning head manufacturing process, beta t ＝1.0；
(3) Calculating to obtain buckling pressure P of the dish-shaped seal head b =1.62 MPa, which is less than 1.8MPa of internal pressure experienced by the head under process conditions;
manufacturing a dish-shaped sealing head by a spinning process according to the calculated size and material, and performing an internal pressure buckling test on the dish-shaped sealing head to obtain a buckling pressure test value of 1.77MPa;
(4) Adjusting the size of the end socket: r is R i /D i ＝0.94，r/D i =0.14, and the buckling pressure P of the dish-shaped seal head is obtained by calculation according to the formula in the step (2) b =1.91 MPa, which is greater than 1.8MPa of internal pressure experienced by the head under process conditions;
(5) According to the size, material and manufacturing process finally determined in the step (4), the dish-shaped seal head is manufactured by a spinning process, and the seal head is subjected to an internal pressure buckling test according to the method described in the literature (Pressure Testing of Large-Scale Torispherical Heads Subjected to Knuckle bucking. Miller C D, grove R B, bennett J G. INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING,1986, 22:147-159), so that the buckling pressure test value is 2.51MPa, which is greater than the pressure required by the process condition by 1.8MPa.
From this, it can be seen that the buckling pressure predicted value P calculated using the formula c Is smaller than the internal pressure of the seal head under the process conditionAnd (3) buckling failure occurs when the end socket product is actually manufactured according to the dimension preliminarily selected in the step (3). However, the buckling pressure predicted value P calculated by the formula is adjusted by the product size of the step (4) c Is larger than the internal pressure of the seal head under the process condition. And then manufacturing again according to the adjusted size, and buckling failure of the end socket product can not occur.
Claims (7)
1. The manufacturing method for preventing buckling failure of the internal pressure thin-wall steel dished end socket is characterized by comprising the following steps of:
(1) According to the design requirement of the pressure vessel, the size, the material and the numerical value of the manufacturing process of the dish-shaped sealing head are preliminarily confirmed, and the method comprises the following steps: inner diameter D of seal head i Radius R of spherical cap region i Radius of transition region r, head thickness t, and material yield strength S y ；
(2) The buckling pressure of the inner pressure steel dished end socket is calculated according to the following formula:
wherein: p (P) b Buckling pressure of the dish-shaped seal head is expressed in MPa; coefficient beta t In connection with the manufacturing process, for spinning and stamping closure heads beta t =1.0 for split head β t ＝0.8；S y The yield strength of the material used for the seal head is expressed in MPa; t is the thickness of the dish-shaped seal head, and the unit is mm; d (D) i The inner diameter of the dish-shaped seal head is in mm; r is R i The radius of the spherical crown area is in mm; r is the radius of the transition zone, and the unit is mm;
(3) If the buckling pressure P of the obtained sealing head is calculated b The internal pressure of the seal head is smaller than the internal pressure of the seal head under the process condition required by design, and after the size or the material of the seal head is required to be adjusted, the calculation is carried out again according to the formula in the step (2);
(4) Repeating the step (3) until the buckling pressure P is calculated b The internal pressure of the seal head is larger than that of the seal head under the process condition;
(5) And (3) manufacturing the dish-shaped seal head according to the seal head parameters used in the final determination of the calculation result in the step (4) and the selected manufacturing process and the conventional operation flow.
2. The method according to claim 1, wherein the diameter-thickness ratio D of the dish-shaped sealing head is ensured when the sealing head is adjusted in size i The/t satisfies: d is not less than 20 i /t≤2000。
3. The method according to claim 1, wherein the ratio R of the radius of the spherical crown area of the dished seal head to the inner diameter of the seal head is ensured when the seal head is adjusted in size i /D i The method meets the following conditions: r is more than or equal to 0.7 i /D i ≤1。
4. The method according to claim 1, wherein the ratio r/D of the radius of the transition zone of the dished seal head to the inner diameter of the seal head is ensured when the seal head is adjusted in size i The method meets the following conditions: r/D is 0.06.ltoreq.r/D i ≤0.2。
5. The method of claim 1, wherein the material of the dished head is carbon steel, low alloy steel, or high alloy steel that meets pressure vessel manufacturing standards.
6. The method according to claim 1, wherein the conventional process for manufacturing a dished closure head, in particular a stamping process, a spinning process or a split forming process, is used for manufacturing the closure head.
7. The method of claim 6, wherein the disc-shaped end enclosure is manufactured by a split forming process when the inner diameter Di is greater than or equal to 4 meters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311521143.2A CN117634238A (en) | 2023-11-15 | 2023-11-15 | Manufacturing method for preventing buckling failure of internal pressure thin-wall steel dished end socket |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311521143.2A CN117634238A (en) | 2023-11-15 | 2023-11-15 | Manufacturing method for preventing buckling failure of internal pressure thin-wall steel dished end socket |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117634238A true CN117634238A (en) | 2024-03-01 |
Family
ID=90032992
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311521143.2A Pending CN117634238A (en) | 2023-11-15 | 2023-11-15 | Manufacturing method for preventing buckling failure of internal pressure thin-wall steel dished end socket |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117634238A (en) |
-
2023
- 2023-11-15 CN CN202311521143.2A patent/CN117634238A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103761365B (en) | High-temperature pressure vessel creep fatigue strength design method based on service life | |
| CN106439313A (en) | Multi-petal inclined-surface hoop and pipe connector thereof | |
| Leonov et al. | Titanium alloys in steam turbine construction | |
| CN117634238A (en) | Manufacturing method for preventing buckling failure of internal pressure thin-wall steel dished end socket | |
| CN110083922B (en) | Method for preventing buckling failure in steel oval end socket | |
| CN117494482A (en) | Calculation method of high-pressure thick-wall spherical shell outer wall crack stress intensity factor | |
| CN112364540A (en) | Method for calculating limit internal pressure of concentric reducer pipe with double defects | |
| CN112347414A (en) | Single-defect bent pipe limit internal pressure calculation method | |
| CN111611680B (en) | Manufacturing method of internal pressure steel elliptical head based on failure mode design | |
| CN105081705B (en) | The preparation method of high pressure nitrogen spheric holder | |
| Parker¹ et al. | Safe Life Design of Gun Tubes Some Numerical Methods and Results | |
| CN112347583B (en) | Method for calculating limit internal pressure of double-defect-contained bent pipe of booster station | |
| EP3869083B1 (en) | Gas pressure accumulator | |
| Shinkin | Influence of non-linearity of hardening curve on elasticoplastic bend of rectangular rod | |
| CN110083961B (en) | System for acquiring strength and airtightness of turbine flange | |
| CN106971033A (en) | Flange bolt prefastening load design method based on nonlinear gasket | |
| CN114896724A (en) | Design method for allowable compressive stress of axial compression cylinder | |
| CN117763747A (en) | Manufacturing method of dish-shaped end socket with plastic collapse resistance and internal pressure buckling resistance design | |
| CN107229778A (en) | The compactness assessment method of high-temperature pipe bump joint | |
| CN206683939U (en) | A kind of zirconium alloy tube hydraulic pressure explosion bulge test sealing device | |
| CN106844894B (en) | Method for measuring and calculating compressive strength of gas storage tank of simple pressure container | |
| CN108763686B (en) | Method for checking strength of reinforced sealing flat cover | |
| Du et al. | Nonlinear finite element analysis of a toroidal shell with ring-stiffened ribs | |
| CN213451886U (en) | Fluorine-lined check valve | |
| CN111400838B (en) | Manufacturing method for preventing plastic collapse failure of inner-pressure steel elliptical head |
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 |