CN100577319C - Shape-expanding method of butt welding tube - Google Patents
Shape-expanding method of butt welding tube Download PDFInfo
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- CN100577319C CN100577319C CN200810137285A CN200810137285A CN100577319C CN 100577319 C CN100577319 C CN 100577319C CN 200810137285 A CN200810137285 A CN 200810137285A CN 200810137285 A CN200810137285 A CN 200810137285A CN 100577319 C CN100577319 C CN 100577319C
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Abstract
A bulging method for a welded pipe relates to a bulging method for a tubular structural piece. The invention aims to solve the problem in the prior art that pipe material with low intensity is prior to bulging in the bulging process and is subjected to a bigger local thinning near a welding seam, thereby lowering the intensity of the structure, especially the fatigue intensity. In the invention, an intermediate-shaped workpiece formed in the first step is placed into a mould provided with a mold cavity in an ultimate shape, and then the mold clamping force is exerted upon the combined molds; the two ends of the intermediate-shaped workpiece are sealed by two plunger heads, and high pressure liquid is filled into the intermediate-shaped workpiece; under the inner pressure, the bulging deformation occurs on the CD sections of the thin or low-intensity pipe and the thick or high-intensity pipe, and the welded pipe in the final shape is obtained. The invention avoids the moving of the welding seam caused by the prior deformation of the thin or low-intensity pipe when the one-step bulging is conducted, and the local thinning of the thin or low-intensity pipe and the thick or high-intensity pipe near the seam. Therefore, the fatigue intensity of the tubular molded workpiece can be improved.
Description
Technical field
The present invention relates to a kind of expanding method of tubular structural member.
Background technology
At present, tubing hydroforming technology has obtained using more and more widely at Aeronautics and Astronautics and auto manufacturing, utilizes the various hollow variable cross-section pipe fitting of this explained hereafter to make structure have more lightweight.With the automobile chassis structural member is example, because different parts bears the load difference, so the requirement difference of each several part intensity, rigidity.For the demanding position of strength and stiffness, can be by changing cross sectional shape and size or employing high strength material raising section modulus and bending resistance, torsional property.
For when increasing the component load-bearing ability, exceed the quality that increases member, two kinds of methods can be arranged: the one, it can be designed to thickening degree member, promptly at the position that needs higher-strength and rigidity, adopt bigger thickness,, adopt less thickness at the less position of carrying.When for example making auto parts, come the design elements wall thickness, can make pts wt alleviate 33% according to loading conditions.The 2nd, can adopt the material of different densities to make foreign material welding structural member, as with aluminium alloy and steel welding, adopt high-strength material at the position that requirement of strength is high, adopt low-density low-intensity materials such as aluminium alloy at the position that carrying is little.For this reason, similar with the welding plate stamping technology that present use is more, the butt welding tube forming technique has been proposed.That is: according to the structural-load-carrying capacity needs thickness difference or intensity, tubing that density is different are welded together, make the hollow variable section structure spare of grow degree, this part is compared with common equal thickness tubing member, remove unnecessary material or partly used light material, component strength and rigidity requirement had both been satisfied, alleviate construction weight again, optimized material cost simultaneously.
Germany Mudar﹠amp; The existing simple butt welding tube product of Bender company comes out, and product is used on some sedan limousines.Compare with tailor welded blank forming, butt welding tube is shaped and belongs to a kind of newer forming technique, and research at present also is in the starting stage.Weld movement rule in the thick butt welding tube internal high pressure forming of aluminium alloy difference that Portugal scholar has passed through numerical simulation study, and point out that thickness is bigger more than big more weld movement amount.BJ University of Aeronautics ﹠ Astronautics's comparative study difference thick butt welding tube and the uniform thickness tubular axis difference on energy absorption when compression, point out that the thick pipe of difference has advantages such as light weight, energy absorption capacity is good, initial spike is low, at the vertical endergonic structure design aspect of lightweight vehicle body, have comparatively application prospects, and can improve the passive safety of automobile.
Typical case's butt welding tube structure promptly adopts the tubing welding that external diameter equates, wall thickness does not wait to obtain the thick butt welding tube of difference as shown in Figure 1, and the light wall pipe original depth is t
1, thick pipe original depth is t
2, this butt welding tube is put into mould apply pressure, obtain part shown in Figure 2 by bulging.
The traditional handicraft method will be welded tubing and place mould 1 as shown in Figure 3, apply interior pressure in tubing, make light wall pipe, thick pipe bulging subsides simultaneously mould.But, welding tubing is when carrying out bulging, because tube wall thickness difference, thin part deforms earlier, and deform after the thicker part, often when light wall pipe pastes mould substantially, thick pipe just deforms, because the light wall pipe major part has been pasted mould, when thick pipe bulging, thick pipe will at first expand near weld seam, and weld seam extreme direction outside thick pipe is moved, and makes near the light wall pipe part (the AB section among Fig. 2) of weld seam larger axis take place to elongation, easily cause light wall pipe local reduction to take place near near the position (the B point among Fig. 2) of weld seam, thereby on final part, form the vulnerable area of an annular, in the part use, should concentrate by the easy stress that produces in place, influence the fatigue strength of part integral body.Studies show that, for external diameter 40mm, t
1=1.4mm, t
2The mild steel butt welding tube of=2.8mm is shaped, and light wall pipe B point reduction is higher by 5.2% than the M point, and as shown in Figure 9, wherein, reduction is the percentage that the tubing original depth and the difference of distortion back thickness account for original depth.
If adopt varying strength tubing to make the welding pipe,, in the bulging process, can have the problems referred to above equally even the pipe wall thickness is equal, that is: bulging preferentially takes place in low-intensity tubing, and bigger local reduction takes place, thereby reduce intensity, the especially fatigue strength of structure near weld seam.
Summary of the invention
The objective of the invention is to have the low-intensity tubing that in the bulging process, exists now bulging preferentially takes place for solving, and bigger local reduction takes place near weld seam, thereby reduce the problem of intensity, the especially fatigue strength of structure, a kind of expanding method of butt welding tube is provided.
The object of the present invention is achieved like this: step 1, elder generation insert initial pipe in the initial mould, the after-applied mold clamping force of matched moulds, seal up the two ends of initial pipe with two drifts, in initial pipe, inject highly pressurised liquid then, initial mould retrains the light wall pipe of initial pipe or the outer wall of low-intensity pipe fully, and thick pipe or the double-strength pipe CD section near light wall pipe or low-intensity pipe one side retrained simultaneously, make thick pipe or double-strength pipe CD section pipeline section generation bulging in addition, pipeline section beyond thick pipe or double-strength pipe CD section pastes mould, obtains the intermediate shape workpiece; Step 2, the intermediate shape workpiece that step 1 is shaped are put into the mould with net shape die cavity, the after-applied mold clamping force of matched moulds, seal up the two ends of intermediate shape workpiece with two drifts, in the intermediate shape workpiece, inject highly pressurised liquid, under interior pressure effect, the CD section generation bulging of light wall pipe or low-intensity pipe and thick pipe or double-strength pipe is out of shape, and obtains the butt welding tube of net shape.
Mould is pasted at the middle part of light wall pipe or low-intensity pipe earlier in the deformation process of method of the present invention butt welding tube in step 2, then, increase along with interior pressure, light wall pipe or low-intensity pipe progressively paste mould, and bulging does not take place in the CD section of the thick pipe of bulging or double-strength pipe simultaneously in step 1, because the major part of thick pipe or double-strength pipe has been pasted mould, in this bulging process thick pipe or double-strength pipe substantially can be more outward direction move, position while welding can be constant substantially, so light wall pipe or low-intensity Guan Buhui are subjected to the axial tension stress effect near the weld seam, have avoided the defective of this position local reduction.The present invention avoided a step during bulging because the weld movement that the preferential distortion of light wall pipe or low-intensity pipe causes, the fatigue strength of drip molding has improved near and the local reduction of light wall pipe or the low-intensity pipe weld seam.
Description of drawings
Fig. 1 is the structural representation before the butt welding tube bulging in the background technology, Fig. 2 is the structural representation of the butt welding tube that obtains by bulging in the background technology, Fig. 3 is that the traditional handicraft method will be welded the schematic diagram that tubing places mould, Fig. 4 is the mould in the step 1 and the schematic diagram of butt welding tube, Fig. 5 is the structural representation of the butt welding tube processed in the step 1, Fig. 6 is the mould in the step 2 and the schematic diagram of butt welding tube, Fig. 7 is the schematic diagram of butt welding tube secondary bulging in the step 2, Fig. 8 is the structural representation of the butt welding tube processed in the step 2, Fig. 9 is the curve map from welding seam distance, Figure 10 is the reduction scatter chart, Figure 11 is the reduction scatter chart of different side-play amounts, and Figure 12 is the reduction scatter chart that different transition angle obtains.
The specific embodiment
The specific embodiment one: (referring to Fig. 4～Fig. 8) present embodiment is achieved in that step 1, earlier initial pipe 4 is inserted in the initial mould 2, the after-applied mold clamping force of matched moulds, seal up the two ends of initial pipe 4 with two drifts 3, in initial pipe 4, inject highly pressurised liquid then, initial mould 2 retrains the light wall pipe of initial pipe 4 or the outer wall of low-intensity pipe fully, and thick pipe or the double-strength pipe CD section near light wall pipe or low-intensity pipe one side retrained simultaneously, make light wall pipe or low-intensity pipe indeformable substantially in the bulging process of step 1, make thick pipe or double-strength pipe CD section pipeline section generation bulging in addition, pipeline section beyond thick pipe or double-strength pipe CD section pastes mould, obtains intermediate shape workpiece 5; Step 2, the intermediate shape workpiece 5 that step 1 is shaped are put into the mould 1 with net shape die cavity, the after-applied mold clamping force of matched moulds, seal up the two ends of intermediate shape workpiece 5 with two drifts 3, in intermediate shape workpiece 5, inject highly pressurised liquid, under interior pressure effect, the CD section generation bulging of light wall pipe or low-intensity pipe and thick pipe or double-strength pipe is out of shape, and obtains the butt welding tube 7 of net shape.
The specific embodiment two: the transition region DE section on (referring to Fig. 5 and Fig. 8) present embodiment intermediate shape workpiece 5 has the conical surface transition shape of semi-cone angle α, the value of α should be chosen according to the transition semi-cone angle β of final part end, and the scope of α is 0.9～1.1 β.To guarantee the uniformity of distortion.Other is identical with the specific embodiment one.
The specific embodiment three: (referring to Fig. 5 and Fig. 8) present embodiment α scope is 1.0 β.Other is identical with the specific embodiment two.
The specific embodiment four: (referring to the step 1 of the present embodiment of Fig. 4～Fig. 8) in the forming process of intermediate shape workpiece 5, thick pipe that is retrained by initial mould 2 or double-strength pipe are 10%～20% of thick pipe or double-strength pipe external diameter near the length of the CD section of light wall pipe or low-intensity pipe one side.Other is identical with the specific embodiment one.
The specific embodiment five: (ratio referring to the butt welding tube 7 maximum cross section outer wall girths of the present embodiment net shape of Fig. 4～Fig. 8) and initial pipe 4 initial cross-section outer wall girths is 1.03～1.3.Other is identical with the specific embodiment one.
The specific embodiment six: (referring to the initial pipe 4 that Fig. 4～Fig. 8) present embodiment adopted is to be made by material different-thickness tubing welding of the same race, and the thickness of light wall pipe and the thickness ratio of thick pipe are 0.5～0.9.Other is identical with the specific embodiment one.
The specific embodiment seven: (referring to the initial pipe 4 that Fig. 4～Fig. 8) present embodiment adopted is that the tubing welding of different materials and varying strength is made, and the yield strength of light wall pipe or low-intensity pipe and the yield strength ratio of thick pipe or double-strength pipe are 0.5～0.9.Other is identical with the specific embodiment one.
Figure 10 provides the part reduction distribution curve that traditional one step forming and the present invention are shaped step by step and obtain according to numerical simulation.As seen, one step forming is not owing to change deformation sequence thin, thick pipe, and the reduction changes in distribution is very big in the bulging district.Wherein 0 of abscissa is the weld seam mid point, and is more little from big more, the thick pipe reduction of the near more light wall pipe reduction of welding seam distance.The maximum reduction of light wall pipe reaches 33.7%, the maximum reduction of thick pipe only 22.2%, and sudden change appears in weld seam both sides wall thickness reduction.And adopt substep manufacturing process of the present invention, and because deformation sequence changes, shaping back reduction is very even, the maximum reduction of thin, thick pipe all between 26%～27%, illustrates that the substep shaping has effectively improved deformation uniformity, has avoided local reduction's defective.
Implement substep of the present invention and be shaped, need to determine the shape and size of initial mould 2 shown in Figure 4, mainly refer to Δ L and α angle, the diameter of the small diameter portion of initial mould 2 can be chosen by initial pipe 4 external diameters.The position that the flex point D of intermediate shape workpiece 5 shown in Figure 4 is ordered has two kinds of possibilities, is respectively on the light wall pipe or on the thick pipe.D point position difference, the distortion of weld seam are different constantly: when the D point is positioned on the light wall pipe, light wall pipe and weld seam all can deform when the first step is shaped, and its distortion situation is similar to traditional bulging situation, can not adopt; When the D point is positioned on the thick pipe, when promptly weld seam was lived by one section constraint of the minor diameter of initial mould 2, weld seam did not deform in first step forming process, so D point position should place on the thick pipe.At this, the distance, delta L of definition D point and weld seam is the side-play amount that D order, the reduction distribution curve that obtains when providing different offset L, as seen reduction distribution the most even (d is the tubing original outer diameter) during Δ L=7.5%d; When Δ L＞25%d, it is negative value that thick pipe reduction occurs near welded seam area, and this is because thick pipe wrinkling defective may occur when serious pressurized is serious vertically.Therefore, the D rational position of ordering should be got 10%～20% the position that offset L is a caliber.
Excessive attenuate takes place or the wrinkling problem of hoop occurs near the D point in light wall pipe during for fear of the butt welding tube 7 that is deformed into net shape by intermediate shape workpiece 5, and transition angle α should choose according to the β angle of final part.Figure 12 provides the reduction distribution curve that obtains when transition angle α gets 0.67 β, 1.0 β and 1.33 β respectively, as seen when transition angle α is 1.0 β, reduction distributes the most even when being α=β, this is because the bulging section length of intermediate shape part 5 this moment in the second step bulging process and the equal in length of final part respective regions not have the axial elongation or the compression that add; The light wall pipe reduction increases during α=0.67 β, and thick pipe reduction reduces; Thin during α=1.33 β, thick pipe is sharply increasing near weld seam annex reduction, but is reducing on the contrary from weld seam medium position reduction far away, and wall unevenness is spared property aggravation (wherein β is an angle value, and unit is " degree ").
Claims (7)
1, a kind of expanding method of butt welding tube, it is characterized in that: the expanding method of butt welding tube is achieved in that step 1, earlier initial pipe (4) is inserted in the initial mould (2), the after-applied mold clamping force of matched moulds, seal up the two ends of initial pipe (4) with two drifts (3), in initial pipe (4), inject highly pressurised liquid then, initial mould (2) retrains the light wall pipe of initial pipe (4) or the outer wall of low-intensity pipe fully, and thick pipe or the double-strength pipe CD section near light wall pipe or low-intensity pipe one side retrained simultaneously, make thick pipe or double-strength pipe CD section pipeline section generation bulging in addition, pipeline section beyond thick pipe or double-strength pipe CD section pastes mould, obtains intermediate shape workpiece (5); Step 2, the intermediate shape workpiece (5) that step 1 is shaped are put into the mould (1) with net shape die cavity, the after-applied mold clamping force of matched moulds, seal up the two ends of intermediate shape workpiece (5) with two drifts (3), in intermediate shape workpiece (5), inject highly pressurised liquid, under interior pressure effect, the CD section generation bulging of light wall pipe or low-intensity pipe and thick pipe or double-strength pipe is out of shape, and obtains the butt welding tube (7) of net shape.
2, the expanding method of a kind of butt welding tube according to claim 1, it is characterized in that: the transition region DE section on the intermediate shape workpiece (5) has the conical surface transition shape of semi-cone angle α, the scope of α is 0.9～1.1 β, and β is the transition semi-cone angle of final part end.
3, the expanding method of a kind of butt welding tube according to claim 2 is characterized in that: the scope of α is 1.0 β, and β is the transition semi-cone angle of final part end.
4, the expanding method of a kind of butt welding tube according to claim 1, it is characterized in that: step 1 is 10%～20% of thick pipe or a double-strength pipe external diameter by the length of the CD section of the thick pipe of initial mould (2) constraint or close light wall pipe of double-strength pipe or low-intensity pipe one side in the forming process of intermediate shape workpiece (5).
5, the expanding method of a kind of butt welding tube according to claim 1 is characterized in that: the butt welding tube of net shape (7) maximum cross section outer wall girth is 1.03～1.3 with the ratio of initial pipe (4) initial cross-section outer wall girth.
6, the expanding method of a kind of butt welding tube according to claim 1 is characterized in that: the initial pipe (4) that is adopted is to be made by material different-thickness tubing welding of the same race, and the thickness of light wall pipe and the thickness ratio of thick pipe are 0.5～0.9.
7, the expanding method of a kind of butt welding tube according to claim 1, it is characterized in that: the initial pipe (4) that is adopted is that the tubing welding of different materials and varying strength is made, and the yield strength of light wall pipe or low-intensity pipe and the yield strength ratio of thick pipe or double-strength pipe are 0.5～0.9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810137285A CN100577319C (en) | 2008-10-10 | 2008-10-10 | Shape-expanding method of butt welding tube |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810137285A CN100577319C (en) | 2008-10-10 | 2008-10-10 | Shape-expanding method of butt welding tube |
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| CN101376146A CN101376146A (en) | 2009-03-04 |
| CN100577319C true CN100577319C (en) | 2010-01-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN200810137285A Expired - Fee Related CN100577319C (en) | 2008-10-10 | 2008-10-10 | Shape-expanding method of butt welding tube |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102962308B (en) * | 2012-12-07 | 2014-12-10 | 哈尔滨工业大学 | Special internal high pressure shaping method for thin-wall welded shell |
| CN104338782B (en) * | 2013-07-30 | 2016-08-24 | 宝山钢铁股份有限公司 | A kind of processing method not waiting Welding Thick Pipe |
| CN104772566A (en) * | 2014-01-10 | 2015-07-15 | 宝山钢铁股份有限公司 | Processing method for non-uniform thickness welded pipe |
| CN103736811B (en) * | 2014-01-23 | 2016-04-27 | 哈尔滨工业大学 | Adopt the method axially not waiting the wall thickness variable diameters pipe fittings such as wall thickness pipe shaping |
| CN106734419B (en) * | 2015-11-23 | 2018-11-30 | 宁波思明汽车科技股份有限公司 | A kind of elbow member bulging prevents the corrugated method of interior angle |
| CN109175061B (en) * | 2018-07-25 | 2020-02-21 | 南京航空航天大学 | Electric auxiliary heating forming device and method for dissimilar material pipe fitting with complex section |
-
2008
- 2008-10-10 CN CN200810137285A patent/CN100577319C/en not_active Expired - Fee Related
Non-Patent Citations (4)
| Title |
|---|
| FEA on deformation behavior of tailor-welded tube inhydroforming. Gang Liu等.Journal of Materials Processing Technology,Vol.187-188 . 2007 |
| FEA on deformation behavior of tailor-welded tube inhydroforming. Gang Liu等.Journal of Materials Processing Technology,Vol.187-188. 2007 * |
| 差厚拼焊管内高压成形焊缝移动规律. 初冠南等.材料科学与工艺，第16卷第1期. 2008 |
| 差厚拼焊管内高压成形焊缝移动规律. 初冠南等.材料科学与工艺，第16卷第1期. 2008 * |
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