CN106248277A - A kind of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress prediction and verification method - Google Patents

Abstract

The invention discloses a kind of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress prediction and verification method, including: employing is cut ring test and is predicted the residual stress of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe, obtains the predictor formula of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress；Use strain gauge method that Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress predictor formula is verified, several foil gauges are the most equidistantly sticked at outer surface of tube wall, corresponding residual stress can be calculated by the strain value measured by foil gauge, compare difference with the predictive value of residual stress within 20% by obtaining the residual stress meansigma methods of each point, then predictor formula is the most feasible.Use the inventive method to improve the quality of spiral welded pipe, expand its range, reduce the cost that pipeline engineering is built, verify correctness and the feasibility of this Forecasting Methodology.

Description

A kind of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress prediction and verification method

Technical field

The invention belongs to technical field of measurement and test, relate to one and to Hi-grade steel large-caliber spiral welded tube residual stress level and divide The method that cloth carries out testing and verifying, it is adaptable to grade of steel >=X70, diameter >=900, molding welding manner is: spiral submerged arc welded.

Background technology

In order to reduce cost, improve transfer efficiency, pipe-line construction is rapidly to distance, high discharge pressure and complicated region Development.Hi-grade steel, heavy caliber conveying welded tube have become the developing direction of current pipe-line.Spiral submerged welded pipe be by Hot-rolled sheet coil is continuously shaped in shaping machine set to be welded, and its moulding process is different from straight-line joint submerged arc welding tube, and weld seam form is also Different.Inconsistent owing to pressing direction and sheet material to deliver direction under format roll in forming process, the adjustment of format roll is likely to result in it Stress is different, and spiral submerged welded pipe is in the fabrication process, without cold expanding operation, so the residual stress of spiral submerged welded pipe State is more complicated.The bigger residual tension of internal existence is to limit the one of the main reasons that spiral welded pipe uses, and is also spiral shell One of weak link of rotation submerged-arc welded (SAW) pipe, and along with the raising of welded tube grade of steel and the increase of wall thickness, this problem will be more prominent Go out.

Residual stress meeting Welded Pipe workmanship and serviceability produce impact, are to produce body stress corrosion and various weldering One of main mechanical factor connecing crackle；Under the conditions of under arms, especially under the conditions of low temperature and dynamic loading, can drop to some extent The bearing capacity of low welded tube and service life；Additionally can affect the dimensional stability of welded tube.And along with the raising of grade of steel, wall Thick increase, the difficulty being controlled residual stress by being adjusted to shape parameter in forming process also can increase.Therefore, in advance Survey and test Hi-grade steel large-caliber spiral welded tube residual stress, analyze its technological factor produced, so right during tubulation The residual stress of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe is controlled, and has very important significance, and can improve spiral welded pipe Quality, its range that expands, reduce the cost that pipeline engineering is built.

Cut ring test method simple and easy to do, apply wider in the production of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe.The method Ultimate principle be by along welded tube axially by pipeline cut, often there is corresponding change in location in such otch both sides, from And residual stress stored in pipeline is discharged.The change in location (displacement) occurred according to otch both sides, according to one Determine program and just can extrapolate residual stress.

According to literature survey analysis, the most more the welded tube residual stress calculation formula of maturation, the most only With cutting ring test as monitoring the method for residual stress in producing, open spacing as the index weighing residual stress with otch. Patent ZL2007101181324 " the residual stress calculation method of spiral seam submerged-arc welding pipe " is although proposing spiral seam submerged-arc welding pipe The evaluation calculation method of middle residual stress, but the phenomenon occurred after cutting ring due to Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe is more Complicated, it is still necessary to the evaluation calculation method of residual stress in spiral seam submerged-arc welding pipe is carried out perfect.Further, for being proposed Method also should use a kind of method to carry out verification experimental verification, to verify the correctness of the method.

Summary of the invention

For solving drawbacks described above present in prior art, it is an object of the invention to provide a kind of for the big mouth of Hi-grade steel The complicated phenomenon that footpath spiral submerged welded pipe is shown after cutting ring test, proposes the evaluation calculation method of its residual stress, in order to The residual stress of spiral welded pipe it is evaluated and controls, improving the quality of spiral welded pipe, expanding its range, reducing pipeline The cost of engineering construction.The Hi-grade steel large-caliber spiral welded tube residual stress predictor formula proposed for the present invention, it is proposed that one Plant and use strain gauge method, to verify correctness and the feasibility of this Forecasting Methodology when cutting ring test to what it was verified.

The present invention is realized by following technical proposals.

A kind of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress prediction and verification method, comprise the steps:

(1) use and cut ring test the residual stress of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe is predicted:

1) using and cut ring test and cut vertically by spiral seam submerged-arc welding pipe, tube section cut both sides can occur the changing of the relative positions vertically Δ z, circumferentially open Δ L, and place, both sides circumference also can occur the radial misalignments of Δ r；

2) green diameter setting steel pipe is h as D, pipe thickness, after cutting the most vertically, and all directions under cylindrical-coordinate system Strain be analyzed；

3) there is the initial condition stress distribution corresponding to three direction change of shape in pipeline section after cutting ring test and cutting；With The principle of stacking of Elasticity gives the macro-stress distribution of complex deformation situation after pipeline section cuts, wherein axile displacement and week Embodying the part of macro-stress in pipeline section to opening, radial misalignments reflects the inhomogeneities that pipeline section internal stress is distributed；Cut ring Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress τ in test^* _ResidualPredictor formula as follows:

In formula: E is elastic modelling quantity, MPa；H is wall thickness, mm；D is outer diameter of steel pipes, mm；Δ L is pipeline section circumference joint open, mm；Δ z is pipeline section axile displacement, mm；Δ r is pipeline section radial misalignments, mm；

(2) use strain gauge method that Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress predictor formula is verified:

1) to cutting the spiral seam slugging pipe pipeline section of ring test, several are the most equidistantly sticked at outer surface of tube wall Foil gauge, then carries out cutting ring test, is cut vertically by pipeline section, and test record pipeline section cuts on before and after's foil gauge vertically Reading changes；

2) corresponding residual stress can be calculated by the strain value measured by foil gauge；

3) strain value recorded according to each point foil gauge calculate corresponding each point residual stress τ '_max, then by each point Residual stress τ '_maxAverage, obtainWillWith based on the Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe cutting ring test Residual stress predictive value τ *_ResidualCompare, if the residual stress meansigma methods of each pointWith residual stress predictive value τ *_ResidualDifference Value is within 20%, then the predictor formula of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress is the most feasible.

Further, described step (2)-1) in, the most equidistantly stick the test of several foil gauges at outer surface of tube wall Record pipeline section cuts the reading change on before and after's foil gauge vertically.

Further, described step (2)-2) in, the strain value measured by foil gauge calculate corresponding residual stress, logical Cross following method to obtain:

During calculating, taking 0 ° of direction parallel with circumference, 90 ° of directions are axial along pipeline；Then principal stress is:

In formula, σ₁For maximum principal stress, MPa；σ₂For minimum principal stress, MPa；

ε_0°For the strain in 0 ° of direction of welded tube, μ ε；ε_90°For the strain in 90 ° of directions of welded tube, μ ε；ε_45°For i.e. becoming with welded tube circumference The strain in 45 ° of directions, μ ε；ν is Poisson's ratio；E is elastic modelling quantity；

Corresponding maximum shear stress is,

${{\mathrm{\τ}}^{\′}}_{\max }=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_2}{2}---\left(4\right)$

Maximum principal stress and angle 2 φ in 0 ° of direction:

$tg2\mathrm{\φ}=\frac{2{\mathrm{\ϵ}}_{45}-{\mathrm{\ϵ}}_0-{\mathrm{\ϵ}}_{90}}{{\mathrm{\ϵ}}_0-{\mathrm{\ϵ}}_{90}}---\left(5\right).$

Further, the direction that described 0 ° of direction is i.e. parallel with welded tube circumference.

Further, described 90 ° of directions are i.e. along welded tube axially direction.

The present invention is directed to the prediction of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress and checking, it is proposed that a kind of based on cutting The residual stress prediction computational methods and verification method based on strain gauge method of the method for ring test, can produce following effect:

(1) the Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress evaluation calculation method that the present invention proposes can be used for it Residual stress is evaluated and controls, thus improves the quality of Hi-grade steel large-caliber spiral welded tube, expands its range, reduces The cost that pipeline engineering is built.

(2) method verifying Hi-grade steel large-caliber spiral welded tube residual stress predictor formula that the present invention proposes can Hi-grade steel large-caliber spiral welded tube residual stress predictor formula for proposing the present invention is verified, to confirm its correctness And feasibility；Also can use when carrying out and cutting ring test, to realize Hi-grade steel large-caliber spiral welded tube residual stress simultaneously Prediction and test.

Accompanying drawing explanation

Fig. 1 (a), (b) are the welded tube schematic appearance after cutting around-France cutting vertically.

Detailed description of the invention

The invention will be described in further detail with embodiment below in conjunction with the accompanying drawings, but is not intended as doing invention any limit The foundation of system.

One Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress of the present invention prediction and verification method, including following step Rapid:

(1) use and cut ring test the residual stress of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe is predicted:

1) using and cut ring test and cut vertically by spiral seam submerged-arc welding pipe, tube section cut both sides can occur the changing of the relative positions vertically Δ z, circumferentially open Δ L, and place, both sides circumference also can occur the radial misalignments of Δ r；

2) green diameter setting steel pipe is h as D, pipe thickness, after cutting the most vertically, and all directions under cylindrical-coordinate system Strain be analyzed；

3) there is the initial condition stress distribution corresponding to three direction change of shape in pipeline section after cutting ring test and cutting；With The principle of stacking of Elasticity gives the macro-stress distribution of complex deformation situation after pipeline section cuts, wherein axile displacement and week Embodying the part of macro-stress in pipeline section to opening, radial misalignments reflects the inhomogeneities that pipeline section internal stress is distributed；Cut ring Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress τ in test^* _ResidualPredictor formula as follows:

In formula: E is elastic modelling quantity, MPa；H is wall thickness, mm；D is outer diameter of steel pipes, mm；Δ L is pipeline section circumference joint open, mm；Δ z is pipeline section axile displacement, mm；Δ r is pipeline section radial misalignments, mm；

(2) use strain gauge method that Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress predictor formula is verified:

1) to cutting the spiral seam slugging pipe pipeline section of ring test, several are the most equidistantly sticked at outer surface of tube wall Foil gauge, then carries out cutting ring test, is cut vertically by pipeline section, and test record pipeline section cuts on before and after's foil gauge vertically Reading changes；

2) corresponding residual stress can be calculated by the strain value measured by foil gauge；

During calculating, taking 0 ° of direction parallel with circumference, 90 ° of directions are axial along pipeline；Then principal stress is:

In formula, σ₁For maximum principal stress, MPa；σ₂For minimum principal stress, MPa；

ε_0°For the strain in 0 ° of direction of welded tube (i.e. parallel with welded tube circumference direction), μ ε；ε_90°For (i.e. edge, 90 ° of directions of welded tube Welded tube axially direction) strain, μ ε；ε_45°For the strain in i.e. circumferential with welded tube direction at 45 °, μ ε；ν is Poisson's ratio；E is bullet Property modulus；

Corresponding maximum shear stress is,

${{\mathrm{\τ}}^{\′}}_{\max }=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_2}{2}---\left(4\right)$

Maximum principal stress and angle 2 φ in 0 ° of direction:

$tg2\mathrm{\φ}=\frac{2{\mathrm{\ϵ}}_{45}-{\mathrm{\ϵ}}_0-{\mathrm{\ϵ}}_{90}}{{\mathrm{\ϵ}}_0-{\mathrm{\ϵ}}_{90}}---\left(5\right).$

3) strain value recorded according to each point foil gauge calculate corresponding each point residual stress τ '_max, then by each point Residual stress τ '_maxAverage, obtainWillWith based on the Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe cutting ring test Residual stress predictive value τ *_ResidualCompare, if the residual stress meansigma methods of each pointWith residual stress predictive value τ *_ResidualDifference Value is within 20%, then the predictor formula of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress is the most feasible.Cut around-France along axle Welded tube outward appearance after cutting is shown in Fig. 1 (a), (b).

Specific embodiment is given below the present invention is further elaborated.

For X80 1219mm × 18.4mm spiral submerged welded pipe, cut a length of 200mm pipeline section and carry out cutting ring test, cut Mouthful circumference joint open be 50mm, the amount of axially offsetting be the 0mm amount of being radially staggered be 10mm, then use the present invention propose Hi-grade steel big Bore spiral submerged welded pipe residual stress Forecasting Methodology, the residual stress of this welded tube is 57.4MPa.

For the pipeline section of above-mentioned X 80 1219mm × a length of 200mm of 18.4mm spiral submerged welded pipe, outside tube wall, survey edge Even circumferential stick 8 foil gauges, then pipeline section is cut vertically, and tests pipeline section and cut vertically on before and after's foil gauge Reading change and pipeline section cut after circumferential joint open, otch both sides displacement vertically and magnitude of misalignment radially. Table 1 cuts, for propose by the present invention, residual-stress value and the strain gauge method test result that ring test residual stress predictor formula provides Contrast.Visible, the residual stress meansigma methods of pipeline section each pointWith residual stress predictive value τ *_ResidualDifference be about 17%.

What table 1 present invention proposed cuts residual-stress value and the strain gauge method test that ring test residual stress predictor formula provides Comparative result

The invention is not limited in above-described embodiment, on the basis of technical scheme disclosed by the invention, the skill of this area Art personnel are according to disclosed technology contents, it is not necessary to some of which technical characteristic just can be made one by performing creative labour A little replacements and deformation, these are replaced and deformation is the most within the scope of the present invention.

Claims (5)

1. a Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress prediction and verification method, it is characterised in that include following Step:

(1) use and cut ring test the residual stress of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe is predicted:

1) use and cut ring test spiral seam submerged-arc welding pipe is cut vertically, tube section cut both sides can occur vertically changing of the relative positions Δ z, Circumferentially open Δ L, and place, both sides circumference also can occur the radial misalignments of Δ r；

2) green diameter setting steel pipe is h as D, pipe thickness, and after cutting the most vertically, under cylindrical-coordinate system, all directions should Change is analyzed；

3) there is the initial condition stress distribution corresponding to three direction change of shape in pipeline section after cutting ring test and cutting；By elasticity The principle of stacking of mechanics gives the macro-stress distribution of complex deformation situation after pipeline section cuts, wherein axile displacement and circumference Opening and embody the part of macro-stress in pipeline section, radial misalignments reflects the inhomogeneities that pipeline section internal stress is distributed；Cut ring test Middle Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress τ^* _ResidualPredictor formula as follows:

In formula: E is elastic modelling quantity, MPa；H is wall thickness, mm；D is outer diameter of steel pipes, mm；Δ L is pipeline section circumference joint open, mm；Δz For pipeline section axile displacement, mm；Δ r is pipeline section radial misalignments, mm；

(2) use strain gauge method that Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress predictor formula is verified:

1) to cutting the spiral seam slugging pipe pipeline section of ring test, several strains are the most equidistantly sticked at outer surface of tube wall Sheet, then carries out cutting ring test, is cut vertically by pipeline section, and test record pipeline section cuts the reading on before and after's foil gauge vertically Change；

2) corresponding residual stress can be calculated by the strain value measured by foil gauge；

3) strain value recorded according to each point foil gauge calculate corresponding each point residual stress τ '_max, then residual by each point Residue stress τ '_maxAverage, obtainWillWith based on Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual cutting ring test Residue stress predictive value τ *_ResidualCompare, if the residual stress meansigma methods of each pointWith residual stress predictive value τ *_ResidualDifference exist Within 20%, then the predictor formula of Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress is the most feasible.

Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress the most according to claim 1 prediction and verification method, it is special Levy and be, described step (2)-1) in, the most equidistantly stick several foil gauges test record pipeline section at outer surface of tube wall Reading on foil gauge change before and after cutting vertically.

Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress the most according to claim 1 prediction and verification method, it is special Levy and be, described step (2)-2) in, the strain value measured by foil gauge calculate corresponding residual stress, by following side Method obtains:

During calculating, taking 0 ° of direction parallel with circumference, 90 ° of directions are axial along pipeline；Then principal stress is:

In formula, σ₁For maximum principal stress, MPa；σ₂For minimum principal stress, MPa；

ε_0°For the strain in 0 ° of direction of welded tube, μ ε；ε_90°For the strain in 90 ° of directions of welded tube, μ ε；ε_45°For i.e. at 45 ° with welded tube circumference The strain in direction, μ ε；ν is Poisson's ratio；E is elastic modelling quantity；

Corresponding maximum shear stress is,

${{\mathrm{\τ}}^{\′}}_{\max }=\frac{{\mathrm{\σ}}_1-{\mathrm{\σ}}_2}{2}---\left(4\right)$

Maximum principal stress and angle 2 φ in 0 ° of direction:

$tg2\mathrm{\φ}=\frac{2{\mathrm{\ϵ}}_{45}-{\mathrm{\ϵ}}_0-{\mathrm{\ϵ}}_{90}}{{\mathrm{\ϵ}}_0-{\mathrm{\ϵ}}_{90}}---\left(5\right).$

Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress the most according to claim 3 prediction and verification method, it is special Levy and be, the direction that described 0 ° of direction is i.e. parallel with welded tube circumference.

Hi-grade steel large-caliber spiral submerged-arc welded (SAW) pipe residual stress the most according to claim 3 prediction and verification method, it is special Levying and be, described 90 ° of directions are i.e. along welded tube axially direction.