CN1276274A - Technology for manufacturing elbow pipe with straight segment - Google Patents
Technology for manufacturing elbow pipe with straight segment Download PDFInfo
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- CN1276274A CN1276274A CN 00112416 CN00112416A CN1276274A CN 1276274 A CN1276274 A CN 1276274A CN 00112416 CN00112416 CN 00112416 CN 00112416 A CN00112416 A CN 00112416A CN 1276274 A CN1276274 A CN 1276274A
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- elbow
- straight section
- tubing
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- core
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Abstract
A technology for manufacturing elbow pipe with straight segments includes such steps as cutting two ends of a pipe to form two oblique cuts, plugging a inner core mould in elbow form and with diameter equal to the internal diameter of pipe into pipe when it reaches creep deformation, plugging straight-segment forming moulds into the pipes at both ends of inner core mould, loading the pipe in die, and press shaping. Its advantages are low cost, high quality and saving raw material.
Description
The present invention relates to a kind of manufacture method of elbow with straight section.
Pipeline and connector thereof are the strength members in power plant, chemical industry, oil and the pipeline transportation, and special-shaped tube connector (elbow, threeway, valve) almost accounts for 50%.Elbow is a weak link outstanding in pipeline and the connector.Be one of main pipe fitting that bears in the power plant high temperature, high pressure effect as main steam line, be fixed that its stressed and intensity is calculated quite complicated with various suspension and supports; According to the document introduction: all damage in the pipe fitting, shape tube (elbow, threeway, valve) almost accounts for 50%.Elbow is a weak link outstanding in the piping, and the reliability of pipeline is mainly determined by the ability to work of elbow.The ability to work of elbow is relevant with its residing stress state.Find that with the actual measurement of work on the spot stress the stress of elbow arcing point externally carries responsive especially as calculated.The additional external force that variation, piping vibration and the suspension and support operation irregularity etc. that these outer year (pressure and deadweight etc. in not comprising) are mainly derived from piping tube metal heat expansion in starting process cause.If starting the arc cross section is a weld bond, these cycle external force will seriously undermine weld bond intensity, and reduced the service life of elbow.For fear of this weakness, it is necessary that the elbow two ends have straight length.
The elbow arcing point is a stress discontinuity point in the piping, and promptly this stress value is greater than the stress value of initial segmental arc of the elbow of its both sides and straight section part, if this point is a weld bond, its stress value also will increase by 5%; Simultaneously, additional outer carry the especially sensitivity of this point to causing by faults such as piping suspension and supports, this load is the principal element of pipeline damage often.In fact bearing alternate load in its long-term starting and stopping process of main steam pipe system, it is totally unfavorable to weld bond intensity, and behind the long duration of action, weld bond forms crackle or destruction easily.Therefore, just can avoid these unfavorable factors with having the alternative not elbow with straight section of straight section elbow, increase the security of piping intensity greatly, this also is vast pipeline engineering designer's a hope.
Aspect manufacturing and installation, elbow with straight section can reduce and control the ovality of elbow two end interfaces preferably, and ovality has also reduced the bending stress of pipeline section when reducing, when welding is installed, it can be easier to counterpart does not have misalignment, has guaranteed the installation quality of piping.
Elbow with straight section is owing to the superiority of its structure, and it can be widely used in the various pipelines of high, medium and low voltage in the thermal power plant, also is applicable to various industrial pipelines such as chemical industry, oil simultaneously, and it is a kind of new product that is worthy of promotion and application.
Domestic existing unit is developed into lengthening straight length steel elbow, adopts the straight length of flexible elbow two ends lengthening 50mm on the structure, after seamless pipe blanking heating, utilizes external force and fixture clamping fixture, carries out plastic deformation and obtains required deformation.Moulding process has adopted the shaping mechanism technology of rolling and sliding, and every technical indicator of product has all reached standard-required.But the technology cost is higher.Also the method and apparatus of useful high-frequency heating is processed, and equipment investment is big, the energy consumption height, and the utilization rate of utilizing anchor clamps to hold tubing when managing just reduces.
The inventive method is achieved in that a kind of manufacture method of elbow with straight section, it is characterized in that two end sections of tubing are cut into oblique otch, its length equals the length with the elbow of straight section, tubing reach creeping deformation the time the interior core of jumping a queue, the diameter of interior core equals the internal diameter of tubing, interior core be shaped as the elbow of not being with straight section, insert the water chestnut mould that straight section is shaped in addition at the two ends of interior core, insert mould then, and tubing is formed by the forcing press matched moulds.After forcing press discharges, take out water chestnut and pound out in core get final product, for ease of deviating from interior core, interior core outside scribbles lubricant.The diameter of water chestnut is less than the internal diameter of tubing.Tubing reach creeping deformation the time condition be: generally be by heating tubing to deformation temperature, and the thin type pipe can be processed at normal temperatures.Generally after moulding, can heat-treat elbow.
The technological equipment of compacting elbow, directly affect the compacting quality of elbow, it not only should satisfy hot-forming deformation characteristics, make corner dimension accurately, good looking appearance, and to accomplish to make simple and easy, equipment is convenient, operation is reliable, use flexibly, meet safety and economic requirement.90 °, 45 ° high pressure elbow with straight section of the present invention's utilization " the core once moulding method is arranged " explained hereafter.R=1D, 1.5D, external diameter φ 18-529mm, wall thickness 10-100mm, pressure 9.81Mpa-32Mpa, the long 20-100mm of two ends straight section.
Characteristics of the present invention are: 1. manufacturing adds man-hour, and elbow with straight section can be controlled the ovality of elbow two end interfaces preferably; 2. when installing, elbow with straight section and straight tube soldering opening are accurately convenient, do not have misalignment; 3. elbow with straight section has been avoided the weld seam of elbow two ends arcing points, has reduced the uncontinuous stress at this place, and the ability that makes piping bear alternate stress increases; 4. also reduce the additional bending stress of pipeline section when the elbow ovality reduces, reduced the stress level of whole elbow; 5. the weak part of main steam line utilizes the product of the inventive method in the elbow, because arcing point does not have weld bond, ovality improves, and has improved the security of whole piping; 6. satisfied the high-pressure pipe member designing requirement of domestic thermal power plant, can be widely used in the various pipelines of high, medium and low voltage simultaneously; 7. the quality of product reaches related standards, and processing cost is low, and material can make full use of, not waste.And processing cost is lower, and the present invention is particularly useful for the processing of the bigger elbow with straight section of caliber.
The invention will be further described by the following examples:
The manufacture method of elbow of band straight section, two end sections with tubing are cut into oblique otch earlier, its length equals the length with the elbow of straight section, tubing reach creeping deformation the time the interior core of jumping a queue, the diameter of interior core (negative common difference) is equal to or slightly less than the internal diameter of tubing, interior core be shaped as the elbow of not being with straight section, be convenient to the demoulding.Insert the water chestnut mould that straight section is shaped at the two ends of interior core, the water chestnut mould contacts with core in the elbow, inserts mould then, and mould is an external mold, and by hydraulic press or hydraulic press, the forcing press matched moulds forms tubing.After forcing press discharges, take out water chestnut, pound out interior core.For ease of deviating from interior core, interior core outside scribbles lubricating grease or kollag (as containing molybdenum or graphite powder).The diameter of water chestnut is less than the internal diameter of tubing and the external diameter of interior core.Tubing reach creeping deformation the time condition be: generally be by heating tubing to deformation temperature, and the thin type pipe can be processed at normal temperatures.Generally can heat-treat elbow after moulding, heat treatment temperature is decided on material.By heating tubing to deformation temperature is that the temperature of creeping deformation can be according to the difference of material and heating-up temperature is different, and for example the deformation temperature of CrMo steel alloy is about 1000 degrees centigrade.
The technological equipment of compacting elbow, directly affect the compacting quality of elbow, it not only should satisfy hot-forming deformation characteristics, make corner dimension accurately, good looking appearance, and to accomplish to make simple and easy, equipment is convenient, operation is reliable, use flexibly, meet safety and economic requirement.Utilization " the core once moulding method is arranged ", " no core quadratic form method ".Principle is to adopt the length compensation method.
Typical embodiment is: select the representational elbow specification of 90 ° of 1.5D elbow φ, 273 * 25 straight section length a=50mm to process, the particular manufacturing craft of elbow be on the basis that absorbs conventional elbow module design principle, carry out improved.Use the elbow with straight section particular manufacturing craft, the core once moulding method is arranged.External diameter φ 273mm, wall thickness 25mm, pressure 30Mpa, the length of horseshoe is corresponding with two ends straight section appearance, gets 50mm.
The material of making elbow with straight section is a seamless steel pipe, and the common used material trade mark and relevant criterion should meet the regulation of table 1.According to customer requirements, can adopt table 1
Heat treatment: the elbow after the moulding is heat-treated table 2 heat treatment method by table 2 requirement
After the heat treatment, the metallographic structure of elbow and other technical performance should meet the respective material standard code.Attachment and oxide skin surfaces externally and internally that the interior place of elbow should clear up in the heating process in the surface and be produced should be smooth.
| Table 1 | Standard No. |
| Material trademark and relevant criterion correspondence table material trademark | |
| ?20G | ?GB5310 |
| ?A106B | ?ASTMA106B |
| ?St45.8/III | ?DIN17175 |
| ?15CrMoG | ?GB5310 |
| ?1Cr5Mo | ?GB6479 |
| ?12Cr2MoG | ?GB5310 |
| ?12Cr1MoVG | ?GB5310 |
| ?10CrMo910 | ?DIN17175 |
| ?0Cr18Ni9 | ?GB/T14976 |
| ?1Cr18Ni9Ti | ?GB13296 |
| Material trademark | Heat treatment method |
| 20G、A106B、St45.8/III | Can replace normalizing when normalizing, final pressure temperature 〉=900 ℃ |
| 1Cr5Mo | Annealing |
| 15CrMoG、??12Cr2MoG、??12Cr1MoVG、 10CrMo91 | Normalizing+tempering |
| 0Cr18Ni9、1Cr19Ni9Ti | Solution treatment |
Embodiment 2: Institute of Nuclear Power Operation: specification: 90 ° of 1.5D elbow φ 273 * 36 straight section length a=50mm material: 10CrMo910.Pressure 18Mpa also can, the length 50mm of horseshoe.Forming temperature and Technology for Heating Processing are as above shown.
Embodiment 3: Zhenghai oil plant power plant for self-supply: specification: 90 ° of 1.5D elbow φ 168 * 18 straight section length a=40mm material: 12Cr1MoV.Pressure 15Mpa, the length of horseshoe is 40mm.
Embodiment 4: Shanghai Furnace Factory Co., Ltd: specification: 90 ° of 1.5D elbow φ 159 * 20 straight section length a=25mm material: 12Cr1MoV.Pressure 9.81Mpa-32Mpa, the length 25mm of horseshoe.
Embodiment 5: specification: 90 ° of 1.5D elbow φ 30 * 10 straight section length a=25mm materials: thin-wall stainless steel, and pressure 12.81Mpa, the length 25mm of horseshoe, and the thin type pipe can pressurize at normal temperatures.
In a word, 90 °, 45 ° high pressure elbow with straight section of the present invention's utilization " the core once moulding method is arranged " explained hereafter.R=1D, 1.5D, external diameter φ 18-529mm, wall thickness 10-100mm, pressure 9.81Mpa-32Mpa, the length of horseshoe is corresponding with two ends straight section appearance, general 20-100mm.
Apply the coercive method and develop.Because utilizing mould compacting elbow with straight section advantage is the productivity ratio height, the mould adjustment is simple.Design the key that the particular manufacturing craft that is fit to the compacting elbow with straight section has just become to develop this new product.Mould is the technological equipment of compacting elbow, directly affect the compacting quality of elbow, it not only should satisfy hot-forming deformation characteristics, make corner dimension accurately, good looking appearance, and to accomplish to make simple and easy, equipment is convenient, operation is reliable, use flexibly, meet safety and economic requirement.
Claims (3)
1. manufacture method of elbow with straight section, it is characterized in that two end sections of tubing are cut into oblique otch, its length equals the length with the elbow of straight section, tubing reach creeping deformation the time the interior core of jumping a queue, the diameter of interior core equals the internal diameter of tubing, interior core be shaped as the elbow of not being with straight section, insert the water chestnut mould that straight section is shaped in addition at the two ends of interior core, insert mould then, and tubing is formed by the forcing press matched moulds.After forcing press discharges, take out water chestnut and pound out in core get final product, for ease of deviating from interior core, interior core outside scribbles lubricant.
2. by the manufacture method of elbow of the described band straight section of claim 1, the core outside scribbles lubricating grease or kollag (as containing molybdenum or graphite powder) in it is characterized in that.
3. by the manufacture method of elbow of the described band straight section of claim 1, the diameter that it is characterized in that water chestnut is less than the internal diameter of tubing and the external diameter of interior core.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001124161A CN1151900C (en) | 2000-07-24 | 2000-07-24 | Technology for manufacturing elbow pipe with straight segment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001124161A CN1151900C (en) | 2000-07-24 | 2000-07-24 | Technology for manufacturing elbow pipe with straight segment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1276274A true CN1276274A (en) | 2000-12-13 |
| CN1151900C CN1151900C (en) | 2004-06-02 |
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ID=4582276
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB001124161A Expired - Fee Related CN1151900C (en) | 2000-07-24 | 2000-07-24 | Technology for manufacturing elbow pipe with straight segment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1151900C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100563865C (en) * | 2008-03-27 | 2009-12-02 | 二重集团（德阳）重型装备股份有限公司 | Combined shaping mold |
| CN103934326A (en) * | 2014-04-10 | 2014-07-23 | 珠海格力电器股份有限公司 | Machining method and machining equipment for small elbow of heat exchanger |
| CN107363138A (en) * | 2017-08-17 | 2017-11-21 | 燕山大学 | Elbow with straight section die forming method |
-
2000
- 2000-07-24 CN CNB001124161A patent/CN1151900C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100563865C (en) * | 2008-03-27 | 2009-12-02 | 二重集团（德阳）重型装备股份有限公司 | Combined shaping mold |
| CN103934326A (en) * | 2014-04-10 | 2014-07-23 | 珠海格力电器股份有限公司 | Machining method and machining equipment for small elbow of heat exchanger |
| CN103934326B (en) * | 2014-04-10 | 2016-08-17 | 珠海格力电器股份有限公司 | The process equipment of heat exchanger eyesight elbow |
| CN107363138A (en) * | 2017-08-17 | 2017-11-21 | 燕山大学 | Elbow with straight section die forming method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1151900C (en) | 2004-06-02 |
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