With the development of cities and the advancement of urbanization in China, the underground pipeline system in cities is becoming more and more complicated. Functional defects and structural defects caused by disrepa...With the development of cities and the advancement of urbanization in China, the underground pipeline system in cities is becoming more and more complicated. Functional defects and structural defects caused by disrepair and geological uneven settlement of urban water supply facilities are increasingly prominent. The contradiction between the population growth brought by the rapid development of the city and the high-quality and high-value development requirements for the environment has gradually increased, making it more difficult to excavate and repair. Compared with excavation repair, trenchless repair has the characteristics of no impact on traffic, no damage to the environment, short construction period, good construction safety and significant social benefits. Through the summary of flexible lining technology, reference and technical support are provided for the implementation of subsequent similar projects. The trenchless repair and renovation engineering technology of municipal underground pipelines has been recognized by people due to its small interference to the ground, high construction speed, low comprehensive cost, good safety, low carbon emissions and other reasons, and has been gradually introduced and popularized in the field of municipal pipe network construction, renovation and repair.展开更多
The leaching behavior of three types of mortars was investigated using a self-design device which could simulate the field conditions of pipe lining. The results by ICP and ESEM measurement show that the developed sla...The leaching behavior of three types of mortars was investigated using a self-design device which could simulate the field conditions of pipe lining. The results by ICP and ESEM measurement show that the developed slag cement mortar is suitable for the lining of cast iron pipe that is used for delivering drinking water.展开更多
Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which cau...Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which causes the liner to separate from the outer pipe and buckles,affecting the stability of the whole line.In this paper,the buckling response of MLP subjected to bending is investigated to clarify its bending characteristics by employing both experiments,numerical simulation,as theoretical methods.Two types of MLPs were manufactured with GB 45 carbon steel(SLP)and Al 6061(ALP)used as the outer pipe material,respectively.The hydraulic expansion and bending experiments of small-scale MLPs are conducted.In addition to the ovalized shape of the cross-section for the SLP specimens,the copper liner was found to wrinkle on the compressive side.In contrast,the liner of ALP remains intact without developing any wrinkling and collapse mode.In addition,a dedicated numerical framework and theoretical models were also established.It was found both the manufacturing and bending responses of the MLP can be well reproduced,and the predicted maximum moment and critical curvatures are in good agreement with the experimental results.展开更多
High-strength pipeline steel and large diameter line pipes are often used to increase the capacity of transportation and reduce the cost associated with the construction and operation of long-distance gas pipeline pro...High-strength pipeline steel and large diameter line pipes are often used to increase the capacity of transportation and reduce the cost associated with the construction and operation of long-distance gas pipeline projects. China＇ s initiatives to construct long-distance natural gas pipelines has brought in new opportunities for the development of X80 line pipes. Baosteel has designed the optimum chemical composition of X80 with high niobium and low molybdenum content. In addition, a welding experimental platform and a finite element model （FEM） have supported the development of X80 UOE pipes in an efficient and economical way. The application and recent development of X80 UOE pipes were introduced in this paper. To comply with the requirements of the Second West-East Gas Pipeline Project （2^nd WEPP ）, X80 pipeline steel with low carbon bainite microstructure was developed by utilizing the optimized composition and TMCP process. The matching welding material, welding procedure and UOE forming processes for 1 219mm outside diameter X80 UOE pipes were also developed. More than 340 000 t of X80 UOE pipes were produced and applied in the 2^nd WEPP. Furthermore, to meet the prospective demand for long-distance gas pipelines with an annual transportation capacity of over 40 billion m3 ,larger size X80 UOE pipes with 1 422 mm OD × 30. 8 mm WT were trial produced recently. DWTT performance, the main technical challenge for heavier wall pipes, was improved by using optimized microstructural design. The newly developed X80 pipes can be potentially used for larger transportation capacity pipelines in China.展开更多
An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and...An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and mechanical properties prediction technology. 3-D thermomechanical coupled finite element models for simulating hot strip rolling have been developed and the distribution of equivalent plastic strain through the thickness direction of the rolled material by CSP rolling was obtained. Thus the distribution of temperature, strain and strain rate through the thickness of the steel stocks, as well as the microstructure evolution during hot rolling of X60 line pipe steel strip has been investigated by using the developed integrated process modelling system. In addition, the determination and optimization of controllable process parameters during CSP hot strip rolling for the Nb-microalloyed X60 line pipe steel have been implemented, and control strategies such as adopting larger pass reduction in the first stand, arranging appropriate pass interval times and proper rolling speed, to reduce or eliminate mixed grain microstructure of Nb microalloyed strip in CSP processing have been proposed.展开更多
Bimetallic lined steel pipe （LSP） is a new anti-corrosion technology. It is widely used to transport oil, gas, water and corrosive liquid chemicals. At present, the hydroforming pressure for LSP has been investigate...Bimetallic lined steel pipe （LSP） is a new anti-corrosion technology. It is widely used to transport oil, gas, water and corrosive liquid chemicals. At present, the hydroforming pressure for LSP has been investigated theoretically and experimentally by most researchers. However, there are a few reports on the thermal strength of bimetallic LSP. Actually, the bimetallic LSP will be subjected to remarkable thermal load in the process of three layer polyethylene （3PE） external coating. Reverse yielding failure may occur on the inner pipe of the bimetallic LSP when it suffers from remarkable thermal load and residual contact pressure simultaneously. The aim of this paper is to study the thermal load and strength of the bimetallic LSP. A mechanical model, which can estimate the thermal strength of the bimetallic LSP, was established based on the elastic theory and the manufacture of the bimetallic LSP. Based on the model, the correlation between the thermal strength of the bimetallic LSP and residual contact pressure and wall thickness of the inner pipe was obtained. Reverse yielding experiments were performed on the LSP （NT80SS-316L） under different thermal loads. Experiment results are consistent with calculated results from the theoretical model. The experimental and simulation results may provide powerful guidance for the bimetallic LSP production and use.展开更多
In present paper,microstructure is observed by means of OM,SEM,EBSD and TEM analysis on material obtained from X100 linepipe with wall thickness as 20.6mm and outside diameter as 1016mm diameter Grade 690.To study the...In present paper,microstructure is observed by means of OM,SEM,EBSD and TEM analysis on material obtained from X100 linepipe with wall thickness as 20.6mm and outside diameter as 1016mm diameter Grade 690.To study the deformation mechanics,microstructure transformation is also investigated on deformed specimens with different strain level as 0%,5% and 8%.Results show that X100 line pipe material consists mainly of acicular ferrite whose ratio in material reaches 64%,obvious cellular structures formed by tangled dislocation and M/A island distributed in acicular plates indicate abundant dislocation and substructure existed in material.It is measured that line pipe steel has a much finer effective grain size as 2.07μm,which can results in a higher strength and toughness for line pipe steel.Contrast analysis for Kikuchi Pattern reveals that the ratio of large-angle boundary is comparatively higher as 55%,implying that line pipe steel has a good toughness.It is observed that the proportion of small-angle grain boundary increases greatly after material deformed,which consequently results in the increment of dislocation and sub-structure.展开更多
The ceramic lined pipes had been produced by gravitational separation SHS method and influential factors on combustion synthesis was investigated.The experimental results showed that the ceramic lined pipes had been...The ceramic lined pipes had been produced by gravitational separation SHS method and influential factors on combustion synthesis was investigated.The experimental results showed that the ceramic lined pipes had been produced easily under condition that selecting pipes well distributed on the wall thickness ,proper preheating temperature and appropriate additive.展开更多
EBSD characterization of density and dispersion of high angle boundaries was carried out in niobium microalloyed steels of HTP base chemistry with 0.09 wt % Nb,which were thermo-mechanically processed under laboratory...EBSD characterization of density and dispersion of high angle boundaries was carried out in niobium microalloyed steels of HTP base chemistry with 0.09 wt % Nb,which were thermo-mechanically processed under laboratory conditions.Similar studies were carried out in higher grade (X-100 and above) line pipe steels with different chemistries,which were processed under simulation of industrial rolling conditions.The twin objectives are (i) to understand the effect of chemistry and processing parameters on the density and dispersion of high angle boundaries,and (ii) to correlate the microstructure and density of high angle boundaries with strength and fracture properties.The present studies confirm that refinement of austenite grain size prior to pancaking,large strain accumulation in austenite conditioning,alloy design with high hardenability and high cooling rates are essential to control high density and uniformity of dispersion of high angle boundaries in the final microstructure in order to achieve high strength,toughness,low DBTT and consistently 100% ductile shear in DWTT in thermo-mechanically rolled higher grade line pipe steels.展开更多
DANIELI has recently implemented its Coil Quality Estimator (DANIELI-CQETM) system to the Hot Strip Mill of United Metallurgical Company (OMK) at Vyksa,Russia.This system is developed for the purpose of real time asse...DANIELI has recently implemented its Coil Quality Estimator (DANIELI-CQETM) system to the Hot Strip Mill of United Metallurgical Company (OMK) at Vyksa,Russia.This system is developed for the purpose of real time assessment and control of mechanical properties for hot rolled coils.Mechanical properties such as strength,toughness,ductility and hardness are predicted over the entire length of a strip while it is processed.The property estimation is based on the final microstructure as predicted from a group of interconnected physically based metallurgical models,supplemented by Artificial Neural Network.The CQE system is used for prediction and control of properties of HSLA line pipe grades steel and other grades.The system performance,is judged by accuracy and reliability of prediction,has been compared with the physical material testing data from the plant.The results are found to be excellent.CQE is found useful for generation of test certificate of coil,quality assurance,process control,product development,and customer claim assessment.It is used for resource optimization for production,and other operational improvements such as reduction of downgrades.The present paper shares the results of CQE performance for prediction of HSLA line pipe grade steels.展开更多
It is of important significance to study the evolution law of the riverbed near underwater crossing line pipes for ensuring the safe operation of oil and gas pipelines and reducing the risk of damage by waterflood disa...It is of important significance to study the evolution law of the riverbed near underwater crossing line pipes for ensuring the safe operation of oil and gas pipelines and reducing the risk of damage by waterflood disasters.In order to clarify the evolution law of the riverbed near un-derwater crossing line pipes and its negative effects,this paper conductedflume model experiments on underwater crossing line pipes.The physical process of riverbed evolution near pipes was observed and the effect of hydrodynamic conditions on the local pipe scour was studied.What's more,the formation mechanism of local scour at underwater crossing line pipes was revealed.And the following research results were obtained.First,when the waterflow is slow,the riverbed evolution process near underwater crossing line pipes is mainly divided into six stages,including riverbed undercutting,pipe exposure,micro-pore formation,scour hole propagation,pipe suspension and scour equilibrium.Second,vortex and seepageflow are the reasons for the local scour of underwater crossing line pipes.Before pipes are exposed,the silt around the pipes is reduced by vortex.After pipes are exposed,micro-pores occur at the pipe bottom under the joint action of vortex and seepageflow.And thus,local scour is formed.Third,flow velocity and water depth jointly influence the riverbed scour duration of each stage and the maximum scour depth at the pipe bottom.When the Froude number(Fr)is in the range of 0.306e0.808,with the increase of Fr,waterflow gets fast,the maximum scour depth at the pipe bottom increases,the duration for scour equilibrium decreases,the riverbed undercutting depth increases and the riverbed topographically getsflatter.The maximum scour depth at the pipe bottom is 0.9e1.6 times the pipe diameter,and the duration for scour equilibrium is between 1650 min and 2620 min.In conclusion,the experimental results provide important reference for predicting the burial depth of underwater crossing line pipes and ensuring their safe operation.展开更多
This paper carries out the analysis of mechanics of a grip system of three-key-board hydraulic tongs developed for offshore oil pipe lines which has been successfully used in oil fields in China. The main improvement ...This paper carries out the analysis of mechanics of a grip system of three-key-board hydraulic tongs developed for offshore oil pipe lines which has been successfully used in oil fields in China. The main improvement of this system is that a lever frame structure is used in the structural design, which reduces greatly the stresses of the major components of the oil pipe tongs. Theoretical analysis and numerical calculation based on thirteen basic equations developed Show that the teeth board of the tongs is not easy to slip as frequently happens to other systems and is of higher reliability.展开更多
During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing...During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing and loading states during service, the pipeline that is generally used exhibits thicker walls than those that are observed in the line pipe. As such, during pipeline construction, hot-induction-bend and line pipes with different wall thickness are girth-welded. The chemical composition of hot-induction-bend and line pipes differs, with the carbon content being particularly higher in the hot-induction-bend pipe;it also depicts a higher carbon equivalent, which makes it possible to modify the girth of the pipe. In this study, using Baosteel＇ s standard X70M UOE hot- induction-bend and line pipes, solid-wire automatic gas-metal-arc girth welding was performed and the performance of the girth-welded joint was evaluated. Furthermore,the weldability of the pipeline girth and the microstructure of the girth-welded joint were analyzed. The results reveal that Baosteel＇ s standard UOE hot-induction-bend and line pipes exhibit good girth weldability, and their technical quality can be guaranteed in case of consumer field- construction applications.展开更多
In the process of construction and service,high-grade line pipes will get defective,e.g.dents,which will change its stress and strain distribution characteristics and impact its service reliability.In this paper,a X80...In the process of construction and service,high-grade line pipes will get defective,e.g.dents,which will change its stress and strain distribution characteristics and impact its service reliability.In this paper,a X80 line pipe was taken as the research object.The distribution characteristics of the strain field in the X80 line pipe with plain dents with the change of dent depth under external load were analyzed using the finite element analysis software ABAQUS.Then,the strain distribution and microstructure characteristics in the dent zone were explored by conducting prefabrication test on physical dent.Finally,combined with the finite element simulation results,the strain distribution laws of the X80 line pipe with plain dent were discussed.And the following research results were obtained.First,under the same internal pressure,the strain distribution characteristics in the dent zone at different dent depths are similar,i.e.,the strain increases with the increase of the distance from the center of the dent,and decreases rapidly with the increase of the distance after the peak strain.Second,the strain increases with the increase of dent depth,and under the same internal pressure and dent depth,the axial strain is larger than the radial strain at the same location.Third,the greater the dent depth,the stronger the superposition effect of internal pressure and depth on the strain.Fourth,strain hardening occurs on the materials in the initial stage of the dent deformation.With the aggravation of deformation and the extension of dent radius,the strain response ability of materials increases,the grains at the bottom and side walls of the dent zone are elongated along the direction of maximum deformation,the lattice is distorted and strain hardening occurs.As a result,the dislocation density in this zone increases and the interaction occurs between dislocations,as a result,the strength of line steel is enhanced.In conclusion,the research results do well in predicting the stressestrain evolution laws in the process of dent,and provide a theoretical foundation and an experimental basis for studying the influence of mechanical damage on the service safety of pipelines.展开更多
Wet gas can form liquid loading at the lower line pipe sections,so the transportation efficiency will be impacted and the line pipes will be corroded and even blocked.Therefore,to accurately predict the critical liqui...Wet gas can form liquid loading at the lower line pipe sections,so the transportation efficiency will be impacted and the line pipes will be corroded and even blocked.Therefore,to accurately predict the critical liquid-carrying velocity of gas is of great significance to preventing the liquid loading in wet gas line pipes.In view of the gaseliquid two-phase stratified flow in micro-tilting line pipes with low liquid content,this paper newly established a critical liquid-carrying velocity prediction model considering droplet entrainment according to the momentum balance equation of a gaseliquid two-phase flow and the closure relationship of a new gaseliquid interface shape.Then,based on the experimental data,the new model,FLAT model,ARS model,double-circle model and MARS model were verified and their prediction results were compared.Finally,the new model was applied to analyze the effects of pipe dip,operational pressure,liquid density and gas component on the critical liquid-carrying velocity and critical liquid content of natural gasewater and natural gase-60%glycerine with water stratified flow in a microtilting line pipe.And the following research results were obtained.First,with the increase of pipe dip and liquid density,the critical liquidcarrying velocity increases continuously and the critical liquid content decreases gradually.Second,with the increase of operational pressure and heavy component content,the critical liquid-carrying velocity decreases continuously and the critical liquid content increases gradually.In conclusion,the new model is higher in prediction accuracy and its prediction result is better accordant with the experimental value,so it can be used to predict the critical liquid-carrying velocity in wet gas line pipes.展开更多
The development and supporting technologies of high-strain line pipe steel and pipes used for oil and gas pipeline projects in special geological environments(such as earthquake zone,landslide zone,mine goaf and subsi...The development and supporting technologies of high-strain line pipe steel and pipes used for oil and gas pipeline projects in special geological environments(such as earthquake zone,landslide zone,mine goaf and subsidence zone)is one of the international research hotspots,and it is also a major problem that China's major oil and gas pipeline projects have to solve.Focusing on a series of key technical difficulties in the research&development and application of high-strain line pipe steel and pipes,a number of theoretical and technological innovations have been achieved after more than ten years of joint researches.And the main achievements are as follows.First,the method of applying many different parameters(e.g.stress ratio,yield to tensile ratio and uniform elongation(UEL))to comprehensively characterize and evaluate the deformation behavior of steel pipes is proposed,and a technical index system and standard for the new products of X70HD/X80HD high-strain line pipe steel and pipes are established.Second,a complete set of X70HD/X80HD steel plate manufacturing technology is researched and developed,and the high-strain steel plate with the properties of low yield to tensile ratio,high uniform elongation,high stress ratio and high strength and toughness is worked out.Third,the X70HD/X80HD JCOE and UOE high-strain longitudinal submerged arc welded pipe manufacturing technology is researched and developed,reasonable performance matching between a steel pipe and a welding seam is realized,and the performance deterioration in the process of forming,welding,diameter-expending and thermal coating is solved.Fourth,a full-scale test device of steel pipe internal pressure t bending large deformation is independently developed,and the physical simulation based steel pipe deformation test technology is formed.X70HD/X80HD high-strain line pipe steel and pipes have been applied in the West to East Gas Pipeline,the ChinaeMyanmar Pipeline and other major gas pipeline projects in the large scale,and their application effects are remarkable.To satisfy the new needs of pipeline construction and long-term safe operation under complex geological conditions,some suggestions were put forwarded,such as developing new methods of strain-based pipeline design,and researching and developing or improving the supporting technologies suitable for the higher matching requirements of girth weld,such as welding methods,welding materials,welding processes,and girth weld performance quality and defect control requirements.展开更多
High-grade(API 5L X80)and large-diameter(OD 1422 mm)line pipes are used in the Sino-Russian eastern route gas pipeline project for high pressure(12 MPa)transmission,and this can significantly increase the transmission...High-grade(API 5L X80)and large-diameter(OD 1422 mm)line pipes are used in the Sino-Russian eastern route gas pipeline project for high pressure(12 MPa)transmission,and this can significantly increase the transmission capacity and meet China's energy strategic demand.With the increase of steel grade,transmission pressure,pipe diameter and design coefficient,however,ductile crack of line pipes becomes the dominant crack mode,so it is necessary to focus on crack arrest and control study.In this paper,therefore,an intensive study was performed on the Battelle Two-Curve(BTC)method which is the major solution to the calculation of arrest toughness,as well as the crack resistance curve and decompression curve.Based on the study,the principle and application range of the BTC method were confirmed.In addition,a series of analysis were conducted on the issues which occurred when the BTC method was applied to high-strength,high-toughness line pipe steel,and the commonly used modified approaches to BTC calculation results were also provided.After the crack control scheme of the X80 large OD 1422 mm line pipes for the Russian Bovanenkovo-Ukhta was reviewed,the BTC calculation results were corrected on the basis of the design parameters of the Sino-Russian eastern routine gas pipeline project,the Charpy V-notched(CVN)impact energy which meets the project requirement was finally worked out to be 245 J.展开更多
The line pipes with large diameter,thick wall and high steel grade are preferred to meet the requirements of extremely high gas transmission rate(380×10^(8) m^(3)/a)in the Sino-Russian eastern route project.In th...The line pipes with large diameter,thick wall and high steel grade are preferred to meet the requirements of extremely high gas transmission rate(380×10^(8) m^(3)/a)in the Sino-Russian eastern route project.In this paper,the technical standards of line pipes at home and abroad were comparatively analyzed after the research and formulation process of technical specifications of X80 line pipes(OD 1422 mm)used in the above-mentioned project was introduced.The key technical indexes such as chemical components,crack-arrest-toughness values,etc.and its formulation process were discussed.In addition,the development process and product performance of the X80 line pipes(OD 1422 mm)were described.It is proved by trial production and product tests that using X80 line pipes(OD 1422 mm)in this gas project is a rational and effective solution to the following technical issues such as chemical composition control,fracture control and welding stability maintenance.This type of line pipes is proved not only to meet project requirements,but to suit for production cases.As a result,the safety of Sino-Russian eastern route gas pipeline will be guaranteed essentially.The research results in this paper provide a strong technical support for the application of X80 line pipes(OD 1422 mm)in the Sino-Russian eastern route project,and play a guiding role in drawing up the technical specifications of other gas pipeline projects.展开更多
This paper presents the applications of vibration monitoring and a diagnosis technique on the predictive maintenance of pipe line pumps on offshore platforms. The monitored ten pumps are distributed on the past three...This paper presents the applications of vibration monitoring and a diagnosis technique on the predictive maintenance of pipe line pumps on offshore platforms. The monitored ten pumps are distributed on the past three petroleum platforms of the CACT (C: China offshove Southern; A: Agip; C: Chivron; T: Texaco) Operation Group in the Huizhou oil field. By the periodical vibration survey in recent three years, the typical faults and the vibration features of these pumps have been summarized, which set up the basis for efficient predictive maintenance of this key equipment offshore.展开更多
文摘With the development of cities and the advancement of urbanization in China, the underground pipeline system in cities is becoming more and more complicated. Functional defects and structural defects caused by disrepair and geological uneven settlement of urban water supply facilities are increasingly prominent. The contradiction between the population growth brought by the rapid development of the city and the high-quality and high-value development requirements for the environment has gradually increased, making it more difficult to excavate and repair. Compared with excavation repair, trenchless repair has the characteristics of no impact on traffic, no damage to the environment, short construction period, good construction safety and significant social benefits. Through the summary of flexible lining technology, reference and technical support are provided for the implementation of subsequent similar projects. The trenchless repair and renovation engineering technology of municipal underground pipelines has been recognized by people due to its small interference to the ground, high construction speed, low comprehensive cost, good safety, low carbon emissions and other reasons, and has been gradually introduced and popularized in the field of municipal pipe network construction, renovation and repair.
文摘The leaching behavior of three types of mortars was investigated using a self-design device which could simulate the field conditions of pipe lining. The results by ICP and ESEM measurement show that the developed slag cement mortar is suitable for the lining of cast iron pipe that is used for delivering drinking water.
基金Fofinancially supported by the National Natural Science Foundation of China(Grant No.52271288)Peiyang Scholar Initiation Fund from Tianjin University。
文摘Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which causes the liner to separate from the outer pipe and buckles,affecting the stability of the whole line.In this paper,the buckling response of MLP subjected to bending is investigated to clarify its bending characteristics by employing both experiments,numerical simulation,as theoretical methods.Two types of MLPs were manufactured with GB 45 carbon steel(SLP)and Al 6061(ALP)used as the outer pipe material,respectively.The hydraulic expansion and bending experiments of small-scale MLPs are conducted.In addition to the ovalized shape of the cross-section for the SLP specimens,the copper liner was found to wrinkle on the compressive side.In contrast,the liner of ALP remains intact without developing any wrinkling and collapse mode.In addition,a dedicated numerical framework and theoretical models were also established.It was found both the manufacturing and bending responses of the MLP can be well reproduced,and the predicted maximum moment and critical curvatures are in good agreement with the experimental results.
文摘High-strength pipeline steel and large diameter line pipes are often used to increase the capacity of transportation and reduce the cost associated with the construction and operation of long-distance gas pipeline projects. China＇ s initiatives to construct long-distance natural gas pipelines has brought in new opportunities for the development of X80 line pipes. Baosteel has designed the optimum chemical composition of X80 with high niobium and low molybdenum content. In addition, a welding experimental platform and a finite element model （FEM） have supported the development of X80 UOE pipes in an efficient and economical way. The application and recent development of X80 UOE pipes were introduced in this paper. To comply with the requirements of the Second West-East Gas Pipeline Project （2^nd WEPP ）, X80 pipeline steel with low carbon bainite microstructure was developed by utilizing the optimized composition and TMCP process. The matching welding material, welding procedure and UOE forming processes for 1 219mm outside diameter X80 UOE pipes were also developed. More than 340 000 t of X80 UOE pipes were produced and applied in the 2^nd WEPP. Furthermore, to meet the prospective demand for long-distance gas pipelines with an annual transportation capacity of over 40 billion m3 ,larger size X80 UOE pipes with 1 422 mm OD × 30. 8 mm WT were trial produced recently. DWTT performance, the main technical challenge for heavier wall pipes, was improved by using optimized microstructural design. The newly developed X80 pipes can be potentially used for larger transportation capacity pipelines in China.
基金Item Sponsored by National Science and Technology Support Program for 11th Five-Year Plan of China (2006BAE03A08)International Science and Technology Cooperation Program(2006DFB72090)
文摘An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and mechanical properties prediction technology. 3-D thermomechanical coupled finite element models for simulating hot strip rolling have been developed and the distribution of equivalent plastic strain through the thickness direction of the rolled material by CSP rolling was obtained. Thus the distribution of temperature, strain and strain rate through the thickness of the steel stocks, as well as the microstructure evolution during hot rolling of X60 line pipe steel strip has been investigated by using the developed integrated process modelling system. In addition, the determination and optimization of controllable process parameters during CSP hot strip rolling for the Nb-microalloyed X60 line pipe steel have been implemented, and control strategies such as adopting larger pass reduction in the first stand, arranging appropriate pass interval times and proper rolling speed, to reduce or eliminate mixed grain microstructure of Nb microalloyed strip in CSP processing have been proposed.
基金financial support from the National Natural Science Foundation of China (Nos. 51004084, 51274170)the Doctoral Fund of Ministry of Education of China (No. 20105121120002)
文摘Bimetallic lined steel pipe （LSP） is a new anti-corrosion technology. It is widely used to transport oil, gas, water and corrosive liquid chemicals. At present, the hydroforming pressure for LSP has been investigated theoretically and experimentally by most researchers. However, there are a few reports on the thermal strength of bimetallic LSP. Actually, the bimetallic LSP will be subjected to remarkable thermal load in the process of three layer polyethylene （3PE） external coating. Reverse yielding failure may occur on the inner pipe of the bimetallic LSP when it suffers from remarkable thermal load and residual contact pressure simultaneously. The aim of this paper is to study the thermal load and strength of the bimetallic LSP. A mechanical model, which can estimate the thermal strength of the bimetallic LSP, was established based on the elastic theory and the manufacture of the bimetallic LSP. Based on the model, the correlation between the thermal strength of the bimetallic LSP and residual contact pressure and wall thickness of the inner pipe was obtained. Reverse yielding experiments were performed on the LSP （NT80SS-316L） under different thermal loads. Experiment results are consistent with calculated results from the theoretical model. The experimental and simulation results may provide powerful guidance for the bimetallic LSP production and use.
基金supported by the 2010 Oil Tube Application Research Program of China National Petroleum Corporation
文摘In present paper,microstructure is observed by means of OM,SEM,EBSD and TEM analysis on material obtained from X100 linepipe with wall thickness as 20.6mm and outside diameter as 1016mm diameter Grade 690.To study the deformation mechanics,microstructure transformation is also investigated on deformed specimens with different strain level as 0%,5% and 8%.Results show that X100 line pipe material consists mainly of acicular ferrite whose ratio in material reaches 64%,obvious cellular structures formed by tangled dislocation and M/A island distributed in acicular plates indicate abundant dislocation and substructure existed in material.It is measured that line pipe steel has a much finer effective grain size as 2.07μm,which can results in a higher strength and toughness for line pipe steel.Contrast analysis for Kikuchi Pattern reveals that the ratio of large-angle boundary is comparatively higher as 55%,implying that line pipe steel has a good toughness.It is observed that the proportion of small-angle grain boundary increases greatly after material deformed,which consequently results in the increment of dislocation and sub-structure.
文摘The ceramic lined pipes had been produced by gravitational separation SHS method and influential factors on combustion synthesis was investigated.The experimental results showed that the ceramic lined pipes had been produced easily under condition that selecting pipes well distributed on the wall thickness ,proper preheating temperature and appropriate additive.
基金CBMM,BrazilChinese Government scholarship+1 种基金Evraz Inc NA,ReginaNSERC,Canada
文摘EBSD characterization of density and dispersion of high angle boundaries was carried out in niobium microalloyed steels of HTP base chemistry with 0.09 wt % Nb,which were thermo-mechanically processed under laboratory conditions.Similar studies were carried out in higher grade (X-100 and above) line pipe steels with different chemistries,which were processed under simulation of industrial rolling conditions.The twin objectives are (i) to understand the effect of chemistry and processing parameters on the density and dispersion of high angle boundaries,and (ii) to correlate the microstructure and density of high angle boundaries with strength and fracture properties.The present studies confirm that refinement of austenite grain size prior to pancaking,large strain accumulation in austenite conditioning,alloy design with high hardenability and high cooling rates are essential to control high density and uniformity of dispersion of high angle boundaries in the final microstructure in order to achieve high strength,toughness,low DBTT and consistently 100% ductile shear in DWTT in thermo-mechanically rolled higher grade line pipe steels.
文摘DANIELI has recently implemented its Coil Quality Estimator (DANIELI-CQETM) system to the Hot Strip Mill of United Metallurgical Company (OMK) at Vyksa,Russia.This system is developed for the purpose of real time assessment and control of mechanical properties for hot rolled coils.Mechanical properties such as strength,toughness,ductility and hardness are predicted over the entire length of a strip while it is processed.The property estimation is based on the final microstructure as predicted from a group of interconnected physically based metallurgical models,supplemented by Artificial Neural Network.The CQE system is used for prediction and control of properties of HSLA line pipe grades steel and other grades.The system performance,is judged by accuracy and reliability of prediction,has been compared with the physical material testing data from the plant.The results are found to be excellent.CQE is found useful for generation of test certificate of coil,quality assurance,process control,product development,and customer claim assessment.It is used for resource optimization for production,and other operational improvements such as reduction of downgrades.The present paper shares the results of CQE performance for prediction of HSLA line pipe grade steels.
基金supported by the National Natural Science Foundation of China"Soil-pipe-water coupling effect and seismic damage mechanism of buried water pipeline"(No.:51478403)PetroChina Major Science&Technology Project"Sudy and application of key technology for maintaining 30 billion cubic meters of production in Southwest Oil and Gas Field(No:2016E-0610).
文摘It is of important significance to study the evolution law of the riverbed near underwater crossing line pipes for ensuring the safe operation of oil and gas pipelines and reducing the risk of damage by waterflood disasters.In order to clarify the evolution law of the riverbed near un-derwater crossing line pipes and its negative effects,this paper conductedflume model experiments on underwater crossing line pipes.The physical process of riverbed evolution near pipes was observed and the effect of hydrodynamic conditions on the local pipe scour was studied.What's more,the formation mechanism of local scour at underwater crossing line pipes was revealed.And the following research results were obtained.First,when the waterflow is slow,the riverbed evolution process near underwater crossing line pipes is mainly divided into six stages,including riverbed undercutting,pipe exposure,micro-pore formation,scour hole propagation,pipe suspension and scour equilibrium.Second,vortex and seepageflow are the reasons for the local scour of underwater crossing line pipes.Before pipes are exposed,the silt around the pipes is reduced by vortex.After pipes are exposed,micro-pores occur at the pipe bottom under the joint action of vortex and seepageflow.And thus,local scour is formed.Third,flow velocity and water depth jointly influence the riverbed scour duration of each stage and the maximum scour depth at the pipe bottom.When the Froude number(Fr)is in the range of 0.306e0.808,with the increase of Fr,waterflow gets fast,the maximum scour depth at the pipe bottom increases,the duration for scour equilibrium decreases,the riverbed undercutting depth increases and the riverbed topographically getsflatter.The maximum scour depth at the pipe bottom is 0.9e1.6 times the pipe diameter,and the duration for scour equilibrium is between 1650 min and 2620 min.In conclusion,the experimental results provide important reference for predicting the burial depth of underwater crossing line pipes and ensuring their safe operation.
文摘This paper carries out the analysis of mechanics of a grip system of three-key-board hydraulic tongs developed for offshore oil pipe lines which has been successfully used in oil fields in China. The main improvement of this system is that a lever frame structure is used in the structural design, which reduces greatly the stresses of the major components of the oil pipe tongs. Theoretical analysis and numerical calculation based on thirteen basic equations developed Show that the teeth board of the tongs is not easy to slip as frequently happens to other systems and is of higher reliability.
文摘During the process of laying long-distance oil and gas transmission pipelines, the hot-induction-bend method is extensively used when the direction has to be changed. By considering the pipeline＇ s ongoing processing and loading states during service, the pipeline that is generally used exhibits thicker walls than those that are observed in the line pipe. As such, during pipeline construction, hot-induction-bend and line pipes with different wall thickness are girth-welded. The chemical composition of hot-induction-bend and line pipes differs, with the carbon content being particularly higher in the hot-induction-bend pipe;it also depicts a higher carbon equivalent, which makes it possible to modify the girth of the pipe. In this study, using Baosteel＇ s standard X70M UOE hot- induction-bend and line pipes, solid-wire automatic gas-metal-arc girth welding was performed and the performance of the girth-welded joint was evaluated. Furthermore,the weldability of the pipeline girth and the microstructure of the girth-welded joint were analyzed. The results reveal that Baosteel＇ s standard UOE hot-induction-bend and line pipes exhibit good girth weldability, and their technical quality can be guaranteed in case of consumer field- construction applications.
基金supported by the National Key Research&Development Plan,“Damage Effect and Accident Investigation Technologies of the Burning Explosion of Dangerous Chemical Storage Facilities”(Grant No.2016YFC0801204).
文摘In the process of construction and service,high-grade line pipes will get defective,e.g.dents,which will change its stress and strain distribution characteristics and impact its service reliability.In this paper,a X80 line pipe was taken as the research object.The distribution characteristics of the strain field in the X80 line pipe with plain dents with the change of dent depth under external load were analyzed using the finite element analysis software ABAQUS.Then,the strain distribution and microstructure characteristics in the dent zone were explored by conducting prefabrication test on physical dent.Finally,combined with the finite element simulation results,the strain distribution laws of the X80 line pipe with plain dent were discussed.And the following research results were obtained.First,under the same internal pressure,the strain distribution characteristics in the dent zone at different dent depths are similar,i.e.,the strain increases with the increase of the distance from the center of the dent,and decreases rapidly with the increase of the distance after the peak strain.Second,the strain increases with the increase of dent depth,and under the same internal pressure and dent depth,the axial strain is larger than the radial strain at the same location.Third,the greater the dent depth,the stronger the superposition effect of internal pressure and depth on the strain.Fourth,strain hardening occurs on the materials in the initial stage of the dent deformation.With the aggravation of deformation and the extension of dent radius,the strain response ability of materials increases,the grains at the bottom and side walls of the dent zone are elongated along the direction of maximum deformation,the lattice is distorted and strain hardening occurs.As a result,the dislocation density in this zone increases and the interaction occurs between dislocations,as a result,the strength of line steel is enhanced.In conclusion,the research results do well in predicting the stressestrain evolution laws in the process of dent,and provide a theoretical foundation and an experimental basis for studying the influence of mechanical damage on the service safety of pipelines.
基金supported by National Natural Science Foundation of China“Thermodynamic behavior investigation,energy efficiency analysis and structural optimization of longitudinal finned tubes of air-heated vaporizer in the integrated cold energy thermoelectric generator”and“Enhanced heat transfer mechanism and structural optimization of innovative heat transfer tube of open rack vaporizer”(No.:51774237 and 51304160)Shaanxi Provincial Scientific Project for Postdoctors“Study on kinetic behaviors of gaseliquid two-phase swirling flow caused by helical tape in vortex borehole”(No.:20168630)Special Research Program of the Education Department of Shaanxi Province“Integration and optimization of cold energy utilization and light hydrocarbon recycling processes at LNG receiving terminal based on the multi-objective comprehensive evaluation method”(No.:15JK1581).
文摘Wet gas can form liquid loading at the lower line pipe sections,so the transportation efficiency will be impacted and the line pipes will be corroded and even blocked.Therefore,to accurately predict the critical liquid-carrying velocity of gas is of great significance to preventing the liquid loading in wet gas line pipes.In view of the gaseliquid two-phase stratified flow in micro-tilting line pipes with low liquid content,this paper newly established a critical liquid-carrying velocity prediction model considering droplet entrainment according to the momentum balance equation of a gaseliquid two-phase flow and the closure relationship of a new gaseliquid interface shape.Then,based on the experimental data,the new model,FLAT model,ARS model,double-circle model and MARS model were verified and their prediction results were compared.Finally,the new model was applied to analyze the effects of pipe dip,operational pressure,liquid density and gas component on the critical liquid-carrying velocity and critical liquid content of natural gasewater and natural gase-60%glycerine with water stratified flow in a microtilting line pipe.And the following research results were obtained.First,with the increase of pipe dip and liquid density,the critical liquidcarrying velocity increases continuously and the critical liquid content decreases gradually.Second,with the increase of operational pressure and heavy component content,the critical liquid-carrying velocity decreases continuously and the critical liquid content increases gradually.In conclusion,the new model is higher in prediction accuracy and its prediction result is better accordant with the experimental value,so it can be used to predict the critical liquid-carrying velocity in wet gas line pipes.
基金Project supported by the National Key R&D Program of China“Research and Development of High-strain Marine Line Pipes”(No.2018YFC03010300)PetroChina's Major Science&Technology Project“Research on Key Technologies for Controlling Pipe Fracture and Deformation in the Second West-East Gas Pipeline”(No.2009E-0105)+1 种基金“Research and Development of Special Welded Pipes for the Second West-East Gas Pipeline”(No.2009E-0104)CNPC's Science&Technology Infrastructure Program“CNPC Infrastructure Construction of Key Laboratory for Petroleum Tubular Engineering”(No.07H611).
文摘The development and supporting technologies of high-strain line pipe steel and pipes used for oil and gas pipeline projects in special geological environments(such as earthquake zone,landslide zone,mine goaf and subsidence zone)is one of the international research hotspots,and it is also a major problem that China's major oil and gas pipeline projects have to solve.Focusing on a series of key technical difficulties in the research&development and application of high-strain line pipe steel and pipes,a number of theoretical and technological innovations have been achieved after more than ten years of joint researches.And the main achievements are as follows.First,the method of applying many different parameters(e.g.stress ratio,yield to tensile ratio and uniform elongation(UEL))to comprehensively characterize and evaluate the deformation behavior of steel pipes is proposed,and a technical index system and standard for the new products of X70HD/X80HD high-strain line pipe steel and pipes are established.Second,a complete set of X70HD/X80HD steel plate manufacturing technology is researched and developed,and the high-strain steel plate with the properties of low yield to tensile ratio,high uniform elongation,high stress ratio and high strength and toughness is worked out.Third,the X70HD/X80HD JCOE and UOE high-strain longitudinal submerged arc welded pipe manufacturing technology is researched and developed,reasonable performance matching between a steel pipe and a welding seam is realized,and the performance deterioration in the process of forming,welding,diameter-expending and thermal coating is solved.Fourth,a full-scale test device of steel pipe internal pressure t bending large deformation is independently developed,and the physical simulation based steel pipe deformation test technology is formed.X70HD/X80HD high-strain line pipe steel and pipes have been applied in the West to East Gas Pipeline,the ChinaeMyanmar Pipeline and other major gas pipeline projects in the large scale,and their application effects are remarkable.To satisfy the new needs of pipeline construction and long-term safe operation under complex geological conditions,some suggestions were put forwarded,such as developing new methods of strain-based pipeline design,and researching and developing or improving the supporting technologies suitable for the higher matching requirements of girth weld,such as welding methods,welding materials,welding processes,and girth weld performance quality and defect control requirements.
文摘High-grade(API 5L X80)and large-diameter(OD 1422 mm)line pipes are used in the Sino-Russian eastern route gas pipeline project for high pressure(12 MPa)transmission,and this can significantly increase the transmission capacity and meet China's energy strategic demand.With the increase of steel grade,transmission pressure,pipe diameter and design coefficient,however,ductile crack of line pipes becomes the dominant crack mode,so it is necessary to focus on crack arrest and control study.In this paper,therefore,an intensive study was performed on the Battelle Two-Curve(BTC)method which is the major solution to the calculation of arrest toughness,as well as the crack resistance curve and decompression curve.Based on the study,the principle and application range of the BTC method were confirmed.In addition,a series of analysis were conducted on the issues which occurred when the BTC method was applied to high-strength,high-toughness line pipe steel,and the commonly used modified approaches to BTC calculation results were also provided.After the crack control scheme of the X80 large OD 1422 mm line pipes for the Russian Bovanenkovo-Ukhta was reviewed,the BTC calculation results were corrected on the basis of the design parameters of the Sino-Russian eastern routine gas pipeline project,the Charpy V-notched(CVN)impact energy which meets the project requirement was finally worked out to be 245 J.
文摘The line pipes with large diameter,thick wall and high steel grade are preferred to meet the requirements of extremely high gas transmission rate(380×10^(8) m^(3)/a)in the Sino-Russian eastern route project.In this paper,the technical standards of line pipes at home and abroad were comparatively analyzed after the research and formulation process of technical specifications of X80 line pipes(OD 1422 mm)used in the above-mentioned project was introduced.The key technical indexes such as chemical components,crack-arrest-toughness values,etc.and its formulation process were discussed.In addition,the development process and product performance of the X80 line pipes(OD 1422 mm)were described.It is proved by trial production and product tests that using X80 line pipes(OD 1422 mm)in this gas project is a rational and effective solution to the following technical issues such as chemical composition control,fracture control and welding stability maintenance.This type of line pipes is proved not only to meet project requirements,but to suit for production cases.As a result,the safety of Sino-Russian eastern route gas pipeline will be guaranteed essentially.The research results in this paper provide a strong technical support for the application of X80 line pipes(OD 1422 mm)in the Sino-Russian eastern route project,and play a guiding role in drawing up the technical specifications of other gas pipeline projects.
文摘This paper presents the applications of vibration monitoring and a diagnosis technique on the predictive maintenance of pipe line pumps on offshore platforms. The monitored ten pumps are distributed on the past three petroleum platforms of the CACT (C: China offshove Southern; A: Agip; C: Chivron; T: Texaco) Operation Group in the Huizhou oil field. By the periodical vibration survey in recent three years, the typical faults and the vibration features of these pumps have been summarized, which set up the basis for efficient predictive maintenance of this key equipment offshore.
