Recent developments of large diameter X80 UOE line pipes

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.

Automatic girth welding and performance evaluation of the joints of hot-induction-bend and line pipes with different wall thickness

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.

Formation of X-120 M Line Pipe through J-C-O-E Technique

The line pipe forming operation can be divided into two parts, first is to achieve the required shape in terms of curvature and ovality after formation of the line pipe. The curvature and ovality ultimately effects the final dimensional controls at the later stage i.e. after mechanical expansion of the line pipe. The second part is to make right welding joint geometry to make the final long seam weld of line pipe. The welding joint geometry ultimately controls soundness of final seam weld at later stage i.e. during submerged arc welding of the line pipe. As far as curvature or shape of line pipe is concerned, important operation is making the required curvature along the edges of TMCP and ACC (Thermo mechanical controlled processing and accelerated cooling process) plate for line pipe (Plate Edge Crimping press) up to the 150 mm in width minimum and forming of the line pipe at J-C-O press. The selection of dies with proper hardness and curvature in both the operation plays a vital role in the formation of line pipes. The main parameters of selection dies (Tools) are size of line pipe for which dies/tools are to be made i.e. the diameter of line pipe, thickness of line pipe and most important is grade of line pipe (Strength level). The grade or strength level decides amount of spring back behavior of the steel Plate. The spring back behavior again varies from steel mill to steel mill in the same grade of HR plate. This is because the each steel mill has its own manufacturing procedures to produce the TMCP and ACC plate. The plate for line pipe is produced through TMCP (Thermo mechanical controlled processing) and accelerated cooling process. In this process the strength level is achieved by the chemical composition of the slab, thickness of the slab, reheating temperature, roughing temperature at which reduction in the thickness, finish rolling temperature and finally the accelerated cooling temperature rate.

Welding technique and quality of large diameter X70 line pipe for gas transmission of China

X70 grade large diameter line pipe with helical and longitudinal seam SAW was developed and used in West-East Pipeline Project of Petrochina. The operation pressure of the pipeline was designed as 10 MPa, with diameter of 1016 mm OD. This project represents the first high-pressure, large diameter and high strength grade gas pipeline in China. All the factors affecting the safety of the pipeline shall be considered. The welds quality of line pipe is very important for safety of the pipeline. Acicular ferrite type X70 grade pipeline steel was adopted for the base material. The welds performances of X70 line pipes with 1016mm OD and 14.6-21.0 mm WT has reached a very high level, especially of low temperature Charpy V impact toughness of welds metal. Welding technique and quality status of X70 line pipe of China are investigated in this paper.

Experimental,Numerical,and Analytical Studies on the Bending of Mechanically Lined Pipe

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.

Mathematical Model of Microstructure Evolution of X60 Line Pipe Steel During CSP Hot Rolling

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.

Microstructure and Deformation Mechanics of X100 Line Pipe Steel

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.

Microstructure Development for Brittle Fracture Control in Nb Microalloyed Line Pipe Steel

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.

Controlling Properties of HSLA Line Pipe Steels for Oil and Gas Applications

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.

Theoretical and experimental study of the thermal strength of anticorrosive lined steel pipes

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.

ESTIMATION OF RESIDUAL CONTACT PRESSURE IN HYDRAULICALLY EXPANDED CRA-LINED PIPE

The mechanically bonded CRA-lined pipe is developed to meet the need forcorrosion-resistant alloy steel pipe. Residual contact pressure at the interface of lined pipe isimportant factor that governs the quality of lined pipe. A simplified theoretical method ispresented to predict the residual contact pressure created by hydraulic pressure. The calculatingequation related hydro-forming pressure to the residual contact pressure between two metal faces isderived. And the validation of the proposed equation is accomplished by comparing its result tothose obtained by experimental investigation.

HYDROFORMING OF BIMETALLIC LINED PIPE

A new hydroforming process for manufacturing corrosion-resistant-alloy(CRA)-lined pipe is proposed to overcome the disadvantages in existing technologies, and a new kindof hydraulic expansion device for bimetallic CRA-lined pipe has been researched and developed. Itsoperational principal and technical characteristic is also introduced. The stress and strain in theliner and outer pipe during the hydroforming process have been analyzed and the mechanism ofhydraulic expansion method is studied theoretically. The final forming pressure formula is suggestedand the theoretical analysis is verified by experimental investigation. The results indicate thatthe new technology is feasible and can be applied in industrial production.

Mechanics of a Grip System of Three-Key-Board Hydraulic Tongs Developed for Offshore Oil Pipe Lines

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.

Vibration Monitoring and Diagnosis of Pipe-line Pumps on Offshore Platforms

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.

Development of Exterior Anti-corrosion Coating Production Line for Large Diameter Hot Bent Pipes

The epoxy powder exterior anti-corrosion coating production line for bent pipes with a single (double) course production is a technologically advanced bent pipe anti corrosion method with cost efficiency, environment friendliness and stable coating quality. The quality of the coating on the bent pipe fully meets the requirements of the current national and industrial standards. The application of the technology has filled the gap in the bent pipe anti corrosion coating area of China, and leads the world technologically. With this technology the coating quality of the bent pipe has greatly improved, resulting in significant social and economic benefits. With the use of the technology in various large scale pipeline projects such as the "West to East Gas Pipeline Project", it will exhibite a greater potential in the future pipeline projects with a broad application prospect.

Development of the High Toughness Spirally Submerged Arc Welded Pipe Line

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冲击力下薄壁内衬复合管界面黏结强度效应分析

【目的】研究薄壁内衬复合管在受冲击力作用下的界面黏结强度对层间剥离屈曲的影响。【方法】建立薄壁内衬复合管在弹性阶段的非线性分析模型,对薄壁内衬复合管材模态试验与分析模型的分析结果进行对比,验证有限元分析模型可靠性。通过改变衬层与原基层管壁间的界面黏结强度,研究复合管在冲击力下的动态特征。【结果】研究结果表明,当冲击荷载较小、管道变形处于弹性阶段时,薄壁内衬复合管的损伤大都集中在层间界面处。界面黏结强度对层间剥离屈曲有较大的影响,随着层间界面黏结强度的增加,外基层管与内衬层的最大等效应力差值减少。此外,外基层管和内衬层的变形协调性能力随着黏结强度增加而增大,径向层间位移减小,增加了复合管的整体性和连续性。【结论】研究结果可为薄壁内衬修复管道设计方法及层间界面效应分析提供参考。

低频导波检测技术在输油场站应用的效果分析

本文主要是对低频导波检测技术原理和应用进行分析,进而选取本次最优开挖验证点,通过MsS长距离超声导波检测仪在姬塬外输总站管网腐蚀检测过程中的应用效果分析,判断其应用效果具有哪些局限性和优缺点,为后续输油场站常规检测工作提供参考依据。

不锈钢内衬修复复合管层间缺陷处应力分析

为研究不锈钢内衬修复前后复合管道内腐蚀缺陷处的应力分布规律以及修复效果,基于有限元软件,建立含单腐蚀坑缺陷的管道模型,改变腐蚀坑的深厚比,忽略黏结层厚度及对腐蚀坑的填补影响,层间采用黏接行为建立界面相互作用分析模型,将修复前后腐蚀缺陷处的应力进行对比。随着腐蚀缺陷深厚比的增加,管壁腐蚀缺陷处的径向应力、周向应力、Mises应力都有增大的趋势;修复前缺陷处的周向应力最大,且其值与Mises应力相近;经不锈钢内衬修复后,缺陷处的周向应力下降了11.3%,Mises应力下降了7.12%。腐蚀缺陷的深厚比对管道的应力分布有着显著的影响,所以在进行复合管线安全评估时应注意腐蚀深度的影响;在修复前后,管道腐蚀缺陷处的控制应力一直是周向应力,复合管道的失效可依据周向应力进行判断;经不锈钢内衬修复后,原始缺陷处的应力发生了重分布,其周向应力与Mises应力均有减小,修复效果明显。

抽油管的在线漏磁检测技术

由于复杂的工况,抽油管的内、外壁极易发生损伤。目前,抽油管的检测方式主要是将抽油管抽离油井后送至后线检测场地进行检测,造成了时间、人力、物力的浪费。采用漏磁检测方法,开展了抽油管在起管或下管过程中的在线检测;设计了瓦片式磁化结构,建立抽油管漏磁检测的三维仿真模型;针对抽油管的腐蚀缺陷,改变缺陷尺寸参数,研究了缺陷漏磁场的分布特性;研发了抽油管在线漏磁检测系统,在实验室和油田作业现场对抽油管进行在线检测试验。试验结果表明,该系统能够快速高效地完成抽油管的在线检测,为抽油管的损伤监测提供了一些参考。