CN101551244B - Squeeze-expanding test method of tube deformation performance - Google Patents

Squeeze-expanding test method of tube deformation performance Download PDF

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Publication number
CN101551244B
CN101551244B CN2009100720444A CN200910072044A CN101551244B CN 101551244 B CN101551244 B CN 101551244B CN 2009100720444 A CN2009100720444 A CN 2009100720444A CN 200910072044 A CN200910072044 A CN 200910072044A CN 101551244 B CN101551244 B CN 101551244B
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pipe
flattening
bulging
pressure
expanding
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CN2009100720444A
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CN101551244A (en
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何祝斌
王志彪
梁峰
龙建周
郭凤梅
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Harbin Institute of Technology
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Harbin Institute of Technology
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Abstract

A squeeze-expanding test method of tube deformation performance relates to a method for testing the deformation performance of tube. The aim of the invention is to better test and evaluate the deformation performance of tube and provide an accurate and reliable tube deformation performance index for inner high-pressure forming of tube. The method of the invention mainly comprises the following steps: a squeezing process, an expanding process, a process for recording the expanding deformation pressure of tube and obtaining the ultimate expanding coefficient, a process for obtaining the expanding deformation pressure and ultimate expanding coefficient corresponding with different rolling reduction, and a process for finally obtaining the variation curve of expanding deformation pressure and variation curve of ultimate expanding coefficient when the expanding amount of tube gradually increases. The method can obtain the expanding result corresponding with different squeezing deformation amount. The effect of squeezing process to the subsequent expanding deformation performance can be reflected more comprehensively. The confirming of reasonable squeezing deformation amount is facilitated.

Description

The flattening of tube deformation performance-bulging method of testing
Technical field
The present invention relates to a kind of method of testing of tube deformation performance.
Background of invention
Internal high pressure forming is a kind of method of producing hollow variable cross section tubulose part.Tubing is subjected to the effect of internal pressure and laterally bulging takes place during internal high pressure forming, and tubing breaks easily when the bulging degree is big.Therefore, to the deformation performance of tubing particularly the expansion forming performance test and estimate the basis of selecting tubing when being internal high pressure forming, determining technological parameter.
Though adopt traditional stretching experiment can obtain the stretcher strain performance of tubing, the performance when but this can not truly reflect the distortion of tubing generation bulging, this is because bulging when distortion tubing mainly is in the stress state of two-way tension, the stress state when obviously being different from unilateral stretching.So, the expansion forming performance that both at home and abroad all begins to adopt direct bulging to test and test tubing, is burst the index that pressure is often used as evaluation tube bulge performance at the limit bulge coefficient after tube bulge breaks (the maximum variable quantity of pipe diameter and the ratio of initial diameter).
But the bulging distortion not only takes place in tubing in the internal high pressure forming process, often also has processes (shown in Fig. 1 a～1c) such as bending, flattening before bulging.Comparatively speaking, flattening process has more direct and significant effects to last bulging process.Flattening deformation makes tubing become square section or other cross sectional shape from the circular section, and this has just consumed a part of plastic deformation ability of tubing, so the follow-up permission deflection of tubing reduces corresponding.The maximum bulging degree of afterflow amount behind the tubing generation flattening deformation or permission is that we are concerned about the most.And do not have suitable method to test and estimate flattening deformation at present to the tube bulge Effect on Performance.
Summary of the invention
The objective of the invention is in order to test and estimate the deformation performance of tubing better,, and then proposed a kind of flattening-bulging method of testing of tube deformation performance for the internal high pressure forming of tubing provides tube deformation performance index accurately and reliably.
Technical scheme of the present invention is: the flattening of tube deformation performance of the present invention-bulging method of testing realizes according to following steps:
Step 1, the duplicate tubing of a plurality of geometric configuratioies of selection are as pipe to be tested;
Step 2, flattening process: get one of them pipe to be tested, it is placed into flattens on the counterdie and the position of adjusting blank; The closed patrix that flattens makes it contact with the pipe upper surface, makes the flattening patrix depress certain displacement Δ 1 continuously then, and guarantees crackle not occur on the pipe, obtains the flattening amount x of pipe 1x 1=displacement Δ 1 ÷ pipe green diameter D;
Step 3, bulging process: the pipe after will flattening is sealed at both ends, feeds high-pressure liquid medium then in the pipe after flattening and makes pipe generation bulging until breaking;
Step 4, record pipe burst pressure y 1The described pressure that bursts is meant when pipe after the flattening bursts the pressure (unit is MPa) of the high-pressure liquid medium that feeds in it; The mean diameter of the pipe rent after measurement is burst, and then obtain limit bulge coefficient; Limit bulge coefficient k 1=(the mean diameter E1-pipe green diameter D of the pipe rent after bursting) ÷ pipe green diameter D;
Step 5, choose next pipe again and test, and change the drafts that flattens patrix in the flattening process, determine that drafts is a Δ 2, Δ 2＞Δ 1; Repeat above-mentioned steps one then to step 4, obtain flattening amount x 2With limit bulge coefficient k 2By that analogy, progressively improve to flatten the drafts of patrix, choose other pipe respectively and test, correspondingly obtain different drafts Δs 3Δ iCorresponding flattening amount x 3X i, and then obtain bursting pressure y accordingly 3Y iAnd limit bulge coefficient k 3K i
Step 6, record many group experimental data (x by above-mentioned steps 1, y 1), (x 2, y 2) ... (x i, y i) and (x 1, k 1), (x 2, k 2) ... (x i, k i) can obtain along with pipe flattening amount progressively increases the change curve that bursts pressure and the change curve of limit bulge coefficient.
The present invention has following beneficial effect: the present invention adopts the deformation sequence of first flattening, back bulging, (first matched moulds flattens can more to approach common forming high pressure in pipe process, supercharging bulging then), the test result that is obtained has more specific aim and reference value; Adopt this method can obtain the bulging result of different flattening deformation amount correspondences, can reflect of the influence of flattening process more all sidedly, be convenient to determine rational flattening deformation amount follow-up bulging deformation performance.
Description of drawings
Fig. 1 a is the tubing design sketch that is pressed in the tubing in the shape process after bending such as (be pressed in the tubing that shape comprises that bending, matched moulds flatten and supercharging bulging operation), Fig. 1 b is pressed into the tubing design sketch after the matched moulds flattening in the shape process in the tubing, Fig. 1 c is pressed into the tubing design sketch behind the supercharging bulging in the shape process in the tubing; Fig. 2 a is that tubing is installed in the structural representation that flattens on the mould (4 are top shoe in the tubing normal temperature flattening process, 5 is following table), Fig. 2 b is that tubing is installed in the structural representation that flattens on the mould (flattening mould is that mould is flattened on the plane), and Fig. 2 c is that tubing is installed in the structural representation that flattens on the mould (flattening mould is that cambered surface is flattened mould); Fig. 3 a be under the tubing heated condition in the flattening process tubing be installed in the structural representation that flattens on the mould, Fig. 3 b flattens the structural representation on the mould (flattening mould is that mould is flattened on the plane) for tubing under heated condition is installed in, Fig. 3 c flattens the structural representation on the mould (flattening mould is that cambered surface is flattened mould) for tubing under heated condition is installed in; Fig. 4 a is that tubing flattens back bulging synoptic diagram (vertical bulging), and Fig. 4 b is that tubing flattens back bulging synoptic diagram (horizontal bulging); Fig. 5 a is the original cross-sectional view of pipe, and Fig. 5 b is the cross-sectional view after pipe flattens, and Fig. 5 c is the cross-sectional view that pipe bursts back pipe rent.
Embodiment
Embodiment one: shown in Fig. 2 a～2c, Fig. 4 a～4b, Fig. 5 a～5c, the flattening of the described tube deformation performance of present embodiment-bulging method of testing realizes according to following steps:
Step 1, the duplicate tubing of a plurality of geometric configuratioies of selection are as pipe to be tested;
Step 2, flattening process: get one of them pipe to be tested 1, it is placed into flattens on the counterdie 3 and the position of adjusting blank; The closed patrix 2 that flattens makes it contact with pipe 1 upper surface, makes flattening patrix 2 depress certain displacement Δ 1 continuously then, and guarantees crackle not occur on the pipe 1, obtains the flattening amount x of pipe 1 1x 1=displacement Δ 1 ÷ pipe green diameter D; Minimum diameter D1=pipe green diameter D-Δ 1 after pipe flattens; Flatten patrix 2 and flatten counterdie 3 and constitute the flattening mould;
Step 3, bulging process: the pipe 1 after will flattening is sealed at both ends, feeds high-pressure liquid medium then in the pipe 1 after flattening and makes pipe 1 bulging take place until breaking;
Adopt end sealing structure as shown in Figs. 4a and 4b to seal at the two ends of the pipe 1 after flattening, then pipe 1 and end sealing structure vertically are placed on the pressing machine, utilize the pressing machine top shoe to push down the upper end hermetically-sealed construction of pipe 1 to guarantee positiver sealing;
Described end sealing structure comprises constraint ring set 8, resilient ring 9, nut 10, band conical surface pull bar 11 and constraint baffle plate 12, resilient ring 9 is installed in respectively in the two ends of pipe 1, constraint ring set 8 is enclosed within the both ends of pipe 1 respectively, band conical surface pull bar 11 is provided with pressure medium channel 11-1, band conical surface pull bar 11 passes the constraint ring set 8 and the resilient ring 9 at pipe 1 two ends respectively, the big end of band conical surface pull bar 11 is arranged in the inner chamber of pipe 1, be processed with screw thread on the band conical surface pull bar 11, nut 10 is located on the band conical surface pull bar 11, and constraint baffle plate 12 is installed on the nut 10; In pipe 1, feed high-pressure liquid medium by pressure medium channel 11-1;
Step 4, record pipe 1 burst pressure y 1The described pressure that bursts is meant when pipe 1 after the flattening bursts the pressure (unit is MPa) of the high-pressure liquid medium that feeds in it; The mean diameter of pipe 1 rent after measurement is burst, and then obtain limit bulge coefficient; Limit bulge coefficient k 1=(the mean diameter E1-pipe green diameter D of the pipe rent after bursting) ÷ pipe green diameter D;
Step 5, choose next pipe again and test, and change the drafts that flattens patrix 2 in the flattening process, determine that drafts is a Δ 2, Δ 2＞Δ 1; Repeat above-mentioned steps one then to step 4, obtain flattening amount x 2With limit bulge coefficient k 2By that analogy, progressively improve to flatten the drafts of patrix 2, choose other pipe respectively and test, correspondingly obtain different drafts Δs 3Δ iCorresponding flattening amount x 3X i, and then obtain bursting pressure y accordingly 3Y iAnd limit bulge coefficient k 3K iWhat obtain different drafts correspondences at last bursts pressure and limit bulge coefficient;
Step 6, record many group experimental data (x by above-mentioned steps 1, y 1), (x 2, y 2) ... (x i, y i) and (x 1, k 1), (x 2, k 2) ... (x i, k i) can obtain along with pipe flattening amount progressively increases the change curve that bursts pressure and the change curve of limit bulge coefficient.According to different flattening deformation correspondences that above-mentioned experiment obtained burst pressure, limit bulge coefficient, the flattening-bulging combined shaping performance of the pipe of testing can be described.
Embodiment two: shown in Fig. 2 c, present embodiment is in step 2, and the flattening mould that is adopted in the flattening process is that cambered surface is flattened mould.The shape and size of cambered surface are determined according to actual needs.Other step is identical with embodiment one.
Embodiment three: shown in Fig. 2 a～2c, Fig. 4 a～4b, before present embodiment was flattened in step 2, the end of pipe 1 had utilized the end sealing device to seal.Adopt the advantage of present embodiment to be, the end to pipe 1 before flattening seals, and can avoid the end cross-sectional of pipe 1 in the flattening process to change and influences follow-up seal process.Other step is identical with embodiment one or two.
Embodiment four: shown in Fig. 2 a～2c, Fig. 3 a～3c and Fig. 4 a～4b, present embodiment is treated pipe 1 sealed at both ends in step 3 after, in pipe bad 1 before the feeding high-pressure liquid medium, with its horizontal positioned and utilize the packoff at 13 pairs of two ends of pull bar of pipe 1 both sides to retrain.Utilize the packoff at 13 pairs of two ends of pull bar of pipe 1 both sides to retrain to prevent it from being released by the highly pressurised liquid in the pipe 1.Adopt the advantage of present embodiment to be, the bulging experiment can be carried out on ground or other table tops after the flattening described in the step 3, does not need to adopt pressing machine that end seal structure is retrained.Other step is identical with embodiment three.
Embodiment five: shown in Fig. 3 a～3c, Fig. 4 a～4b, present embodiment is in the bulging process of the flattening process of step 2 indication and step 3 indication, pipe 1 all is to deform under heating condition, the heating of pipe 1 can be adopted the mode that heating rod 7 is set flattening on the mould in the flattening process, and the heating of pipe 1 can be adopted the mode that feeds the liquid pressure medium of high temperature (temperature range of high temperature is 50 ℃～350 ℃) in pipe 1 in the bulging process.Adopt the advantage of present embodiment to be, when flattening, pipe 1 is heated and under different temperature, test with bulging, can obtain the flattening-bulging Effect on Performance of deformation temperature, for the hot internal high pressure forming that carries out tubing provides the basis to pipe 1.Heating rod 7 is installed in and flattens in the bottoming hole 6 that has on the mould.Other step is identical with embodiment one or four.

Claims (5)

1. the flattening of a tube deformation performance-bulging method of testing, it is characterized in that: described method realizes according to following steps:
Step 1, the duplicate tubing of a plurality of geometric configuratioies of selection are as pipe to be tested;
Step 2, flattening process: get one of them pipe to be tested (1), it is placed into flattens the position that counterdie (3) is gone up and adjusted blank; The closed patrix (2) that flattens makes it contact with pipe (1) upper surface, makes flattening patrix (2) depress certain displacement Δ 1 continuously then, and guarantees crackle not occur on the pipe (1), obtains the flattening amount x of pipe (1) 1x 1=displacement Δ 1 ÷ pipe green diameter D;
Step 3, bulging process: the pipe after will flattening (1) is sealed at both ends, feeds high-pressure liquid medium then in the pipe (1) after flattening and makes pipe (1) bulging take place until breaking;
Step 4, record pipe burst pressure y 1Describedly burst pipe (1) after pressure is meant flattening when bursting, the pressure of the high-pressure liquid medium that feeds in it; The mean diameter of the pipe after measurement is burst (1) rent, and then obtain limit bulge coefficient; Limit bulge coefficient k 1=(the mean diameter E1-pipe green diameter D of the pipe rent after bursting) ÷ pipe green diameter D;
Step 5, choose next pipe again and test, and change the drafts that flattens patrix (2) in the flattening process, determine that drafts is a Δ 2, Δ 2＞Δ 1; Repeat above-mentioned steps one then to step 4, obtain flattening amount x 2With limit bulge coefficient k 2By that analogy, progressively improve to flatten the drafts of patrix (2), choose other pipe respectively and test, correspondingly obtain different drafts Δs 3Δ iCorresponding flattening amount x 3X i, and then obtain bursting pressure y accordingly 3Y iAnd limit bulge coefficient k 3K i
Step 6, record many group experimental data (x by above-mentioned steps 1, y 1), (x 2, y 2) ... (x i, y i) and (x 1, k 1), (x 2, k 2) ... (x i, k i) can obtain along with pipe flattening amount progressively increases the change curve that bursts pressure and the change curve of limit bulge coefficient.
2. the flattening of tube deformation performance according to claim 1-bulging method of testing is characterized in that: in step 2, what adopted in the flattening process is that cambered surface is flattened mould.
3. the flattening of tube deformation performance according to claim 1 and 2-bulging method of testing, it is characterized in that: before flattening in step 2, the end of pipe (1) has utilized the end sealing device to seal.
4. the flattening of tube deformation performance according to claim 3-bulging method of testing, it is characterized in that: after in step 3, treating pipe (1) sealed at both ends, in pipe (1), feed before the high-pressure liquid medium, its horizontal positioned and the pull bar (13) that utilizes pipe (1) the both sides packoff to two ends is retrained.
5. according to the flattening-bulging method of testing of claim 1 or 4 described tube deformation performances, it is characterized in that: in the bulging process of the flattening process of step 2 indication and step 3 indication, pipe (1) all is to deform under heating condition, the thermal recovery that adds of pipe in the flattening process (1) is flattening the mode that heating rod (7) are set on the mould, pipe in the bulging process (1) add thermal recovery feeds the high-temperature fluid pressure medium in pipe (1) mode.
CN2009100720444A 2009-05-18 2009-05-18 Squeeze-expanding test method of tube deformation performance Expired - Fee Related CN101551244B (en)

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CN104949884B (en) * 2013-12-24 2018-10-30 哈尔滨工业大学 A kind of the coefficient of normal anisortopy Direct Determination of tubing circumferential direction

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CN101412063A (en) * 2008-12-11 2009-04-22 江西昌河航空工业有限公司 Method for expanding high intensity steel tube

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Publication number Priority date Publication date Assignee Title
CN1644264A (en) * 2005-01-21 2005-07-27 哈尔滨工业大学 High-pressure forming method in tubular member for lowering forming pressure
CN1751819A (en) * 2005-10-25 2006-03-29 哈尔滨工业大学 Thermal internal high pressure formation method for light alloy tube (or pipe)
CN101285749A (en) * 2008-05-22 2008-10-15 上海交通大学 Pipes shaping limit curve test device for hydraulic bulging process
CN101412063A (en) * 2008-12-11 2009-04-22 江西昌河航空工业有限公司 Method for expanding high intensity steel tube

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Assignee: Foshan Jinlan Aluminum Factory Co., Ltd.

Assignor: Harbin Institute of Technology

Contract record no.: 2011440000613

Denomination of invention: Squeeze-expanding test method of tube deformation performance

Granted publication date: 20100929

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