Field girth weldability evaluation of X70 UOE pipeline

Based on API STD 1104-2005 and CSA Z662-2007,field girth welding tests and girth weldability evaluations were executed for three types of wall thickness X70 UOE pipeline,in which the most popular main line girth welding method,single-wire automatic gas metal arc welding(GMAW),was used. The welding procedure specification was optimized to achieve a good quality and cold-crack-free girth weld joint without preheating or post-weld heat treatment. In addition,porosities,inclusions,and incomplete fusion defects were avoided. The tensile strength,bending,Vickers hardness,Charpy V-notch impact toughness,and crack tip opening displacement fracture toughness of the girth weld joint were evaluated,and the joint exhibited good mechanical performance. Thus,the field girth weldability of Baosteel's X70 UOE pipeline is excellent for automatic GMAW.     

Evaluation of automatic girth weldability of pipeline in special conditions

To meet the requirements of pipeline consumers abroad, in this study, an automatic gas metal arc welding type of girth welding was performed with a heat input of no more than 0.25 kJ/mm and high-strength solid-wire matching for an X70 M large-diameter UOE pipeline.An integral evaluation of the X70 M pipeline girth weldability was performed with respect to the girth-weld cold-cracking sensitivity during the welding process and the strengthening, hardening, and embrittlement of the girth weld joint after girth welding in especially rigorous welding conditions with accelerated failure characteristics.The performance of the above girth weld joint with joints welded using the main construction-field girth welding procedure was compared to ensure the good girth weldability of the X70 M pipeline.The results of this study have important supervisory significance for field-construction girth welding.Finally, the girth weldability of the X70 M pipeline was found to satisfy the field construction requirements even when the welding conditions are especially rigorous.     

特殊条件下管线钢管自动环缝焊接性研究

根据海外管线钢管用户需求,针对典型规格X70M大口径UOE管线钢管,在不超过0.25 kJ/mm超低热输入以及焊丝高强匹配条件下进行熔化极气体保护自动环缝焊接。通过研究实际焊接过程中环焊接头冷裂纹敏感性、焊后环焊接头强化、硬化与脆化倾向,全面评价X70M管线钢管在这种具有加速失效特征的特殊焊接条件下的环缝焊接性。同时,将特殊条件下X70M管线钢管接头使用性能特征与现场施工正常主流焊接工艺条件下的接头性能指标进行比较,从而证实了X70M管线钢管良好的环缝焊接性,并指出了特殊条件下管线钢管自动环缝焊接性评价结果对现场施工焊接的重要指导意义。结果表明,即使在特殊苛刻焊接条件下,X70M管线钢管焊接性仍能满足现场施工焊接要求。     

管线钢WIC试验对UOE钢管现场施工环焊的指导

WIC试验是加拿大焊接协会20世纪80年代开发的一种用于评价管线钢材料抵抗焊接氢致裂纹能力的试验方法,其反映了管线钢材料的可焊性,尤其是制管后管线钢管现场施工环缝焊接性。因此可根据WIC试验的结果,制定UOE钢管现场施工环焊坡口设计与组对、环缝根焊方法选择与工艺制定、环焊后续处理等方面的指导原则,为相关用户提供技术支撑。     

Girth weldability and welding process of Baosteel X80 UOE linepipes

An analysis of the girth weldability of Baosteel X80 UOE (U-ing-O-ing-Expanding) linepipes was conducted using manual shielded metal arc welding (SMAW) and semiautomatic self-shielded flux cored wire arc welding (FCAW).A technical specification for the optimum quality of a girth welding joint was obtained through a large amount of testing.According to the requirements of America Petroleum Institute(API) standard 1104 and the standards of the 2nd West-East natural gas transmission pipeline project,the mechanical properties of a girth welding joint were estimated.In addition,the effect of the girth welding procedure specifications and the consumable’s suitability on the impact toughness of the girth welding joint was discussed.     

Development and application of Baosteel X80 large diameter UOE longitudinal submerged arc welded pipes

With the increase in energy demand,the demand for oil and gas transmission pipes,particularly high-grade longitudinal submerged arc welded pipes (LSAWs),have been growing in recent years.The construction of the 2nd West-East natural gas transmission pipeline project shows that the oil and gas pipeline construction has entered a new phase of development with X80 pipes being applied in large scales for the first time in China.This paper briefly introduces the 2nd West-East natural gas transmission pipeline project and its main technical requirements with the focus on the features of API standard 5L X80 grade  1219 mm series of U-ing-O-ing-Expanding (UOE) LSAW pipes,which Baosteel developed with the integrated technology for the 2nd West-East natural gas transmission pipeline project.The analysis shows the extra-low carbon content,the high contents of manganese and niobium,the fine microstructure,the high strength,the toughness and the good weldability of X80 pipes meet the requirements of "the technical specification of LSAW linepipes for the 2nd West-East natural gas transmission pipeline project in China".By the end of June 2010,Baosteel had totally produced 322000 t of  1219 mm X80 UOE steel pipes,which have been successfully used in the 2nd West-East natural gas transmission pipeline project,thus filling the gap of the production of large diameter X80 UOE LSAW pipes in China.     

大口径油气管道环焊技术的进展及在宝钢的应用

介绍了当前管道工业的发展及管道焊接技术的进展情况,并阐明了管道全位置下向焊接技术的特性.管道环焊缝是由根焊、热焊、填充焊、盖面焊等不同焊道组成.对常用的手工焊、半自动焊和自动焊接方法在管道环焊缝不同焊道焊接时的应用以及各自特点做了介绍,还对焊接材料的选用、焊接设备的选型作了描述.宝钢铜管厂大口径直缝埋弧焊管(UOE)项目即将投产,投产后大口径焊管产品使用技术的研究势在必行,宝钢应尽快开展大口径UOE焊管的环缝焊接技术的研究,为将来的推广应用提供必要的技术支撑.     

Engineering critical assessment on welding flaws of the X65 UOE girth weld based on CRACKWISE

Focused on the girth weld of a Φ762 × 28. 6 mm( X65) offshore UOE pipe,the fracture toughness properties at different weld joint positions were tested. Meanwhile,the largest size of different cracks under service condition was calculated by using CRACKWISE. The service life of the UOE pipe with postulated crack-like flaws was calculated by considering various fatigue factors,such as vibrations caused by ocean current and fluctuations of inner pressure. The assessment process and results can be used to direct the repair of weld flaws laid in pipes or to assess the reliability of in-serving pipes.     

Research status of corrosion environment failure and safety assessment of pipeline welded joint

Pipeline transportation is an economical,safe,and efficient transportation method for transporting oil,natural gas,mineral slurry,and other fluids.Welding is the most critical construction process in pipeline engineering and is crucial in the safe operation and service of an entire pipeline system.Theoretically,the girth welded joint is the weakest link in a pipeline system.The unevenness of the structure and performance of the joint caused by welding frequently results in the failure of the welded joint before the failure of the base material of the pipe body,causing the pipeline to leak or even break.For steel pipes used in an acidic corrosive medium environment,the integration of the corrosive medium and mechanical load will accelerate the failure of the welded joint.This article reviews the failure modes of pipeline welded joints in acidic corrosive media,including stress corrosion cracking,hydrogen-induced cracking,and corrosion fracture,and corrosion fatigue considering the diffusion and accumulation of H+at the crack tip.It also reviews service pipelines in acidic corrosive media.The general processing technology of pipe joint engineering critical assessment(ECA)is investigated to provide a reference for the future development of technology in this field.     

宝钢UOE大口径直缝埋弧焊管机组的技术特点与优势

宝钢UOE机组是我国第一套现代化大口径直缝埋弧焊管机组,也是世界上装备最先进的大口径直缝埋弧焊生产线.介绍了宝钢UOE机组的概况和特色,并论述了该机组的一贯制体系优势、原料优势和设备优势,对关键的成型和焊接设备的技术特点进行了重点阐述,同时也介绍了宝钢在自主技术方面的研发情况.     

具有优异低温韧性的API X80级别电阻焊接管线钢

介绍X80电阻焊接(ERW)管线钢的本质和特点。厚壁高强管线钢将越来越多地用于高压管线,以提高天然气和石油的输送效率,为了提高X80热轧板卷的材料性能,研究了显微组织、化学成分对强度和韧性的影响。基于此结果,采用热机械控轧工艺(TMCP)技术开发了具有细小析出物和非粗大珠光体或马氏体的超低碳贝氏体铁素体钢,获得了低温用途基材和焊缝性能的良好平衡。     

Investigation of the impact toughness of self-shielded flux-cored wire girth welds for X80 pipelines

Self-shielded flux-cored wire is a convenient and efficient consumable for pipeline field girth welding because of its self-protection characteristic and high deposition rate,especially for remote construction sites in rugged terrain. From the perspective of pipeline safety,the impact toughness of the girth welds is an important factor in pipeline integrity,which determines the crack arrest behavior in the girth welds. Therefore,improving the girth weld impact toughness is of primary importance in the field of pipeline girth welding. Three self-shielded flux-cored wires comprising different chemical composition systems have been applied to large diameter X80 UOE( U-ing-O-ingExpanding) pipeline semi-automatic girth welding,and the impact toughness of the welds has been evaluated by girth weld chemical composition analysis and microstructural analysis using scanning electron microscopy( SEM) and energy dispersive spectrometry( EDS) to investigate pipeline girth weld impact toughness and find ways to improve it.This helps in determining the main factors that influence girth weld impact toughness. Pipeline girth weld impact toughness is mainly determined by the final microstructure produced in the solid-state phase transition. In the as-weld state,acicular ferrite( AF) and fine bainite( FB) are a benefit to the impact toughness. For multilayer semiautomatic self-shielded flux-cored wire welding,the normalizing and tempering function of the latter beads to the initial beads plays an important role in the transition of girth weld microstructure,which affects the impact toughness. The original AF and FB and the corresponding heat treatment microstructure of the fine and uniform block ferrite and pearlite result in very good impact toughness. The following two mechanisms are found to promote the production of AF and FB in the girth weld. First,elements promoting the broadening of the austenitic region,such as Ni,C,Cu,and Mn,induce low temperature phase transitions and restrain the opposing function of Al,which is a benefit to the production of AF and FB. Second,dispersed high-melting-point inclusions,especially Al2O3,induce the nucleated production of AF. The advantageous function of inclusions is determined by their shape,distribution,and dimension. Dispersed spherical inclusions of small dimension are a benefit to the production of AF,and result in good impact toughness.     

Heat Flow during the Autogenous GTA Welding of Pipes

A theoretical and experimental study of heat flow during the welding of pipes was carried out. The theoretical part of the study involves the development of two finite difference computer models: one for describing steady state, 3-dimensional heat flow during seam welding, the other for describing unsteady state, 3-dimensional heat flow during girth welding. The experimental part of the study, on the other hand, includes: measurement of the thermal response of the pipe with a high speed data acquisition system, determination of the arc efficiency with a calorimeter, and examination of the fusion boundary of the resultant weld. The experimental results were compared with the calculated ones, and the agreement was excellent in the case of seam welding and reasonably good in the case of girth welding. Both the computer models and experiments confirmed that, under a constant heat input and welding speed, the size of the fusion zone remains unchanged in seam welding but continues to increase in girth welding of pipes of small diameters. It is expected that the unsteady state model developed can be used to provide optimum conditions for girth welding, so that uniform weld beads can be obtained and weld defects such as lack of fusion and sagging can be avoided.     

Product development of Baosteel HFW 610 Mill

Baosteel’s high-frequency electric resistance welded(HFW) 610 longitudinal seam mill(8 5/8″-24″, the yearly output 300000 t) and UOE 1422 longitudinal submerged arc welding(SAW) mill(20" -56",the yearly output 500000 t) are established in 2005 and 2008,respectively.Product specification covers whole of API 5CT standard and most of API 5L standard,terminating the history of manufacturing the medium and large size pipes at Baosteel.The yearly output increased from 1,200000 t to nearly 2000000 t.HFW 610 mill is oriented at mid size pipes,which are mainly linepipe and welded casing.The designed yearly output of HFW mill is 300000 t,including casing of 90000 t,linepipe of 180000 t,round structural pipe of 15000 t and rectangle structural pipe of 15000 t. The yearly output of oil casing line supporting the welding line is 120000 t,among which including welded casing and seamless casing of 30000 t.Baosteel’s HFW 610 longitudinal seam mill was established on October 27,2005. After the equipment trial run In October,2005 - March,2006 and equipment function examination In April,2006 - June,2006,mass production started in July 2006.And in December 2006,monthly designed capacity was achieved,reaching to 30496.644 t in welding pipe and 28 349.939 t in finished pipe.The output of 2006,2007, 2008 and 2009 was 117 067 t,223 554 t,255 791 t,and 204 424 t,with the comprehensive yield ratio 79.4%, 87.8%,90.80%and 91.92%respectively.This study introduces Baosteel HFW 610 Mill which is the world class,energy conservation and environmental protection enterprise,including product orientation,process and new product development.     

石油钻杆的摩擦焊接和焊缝热处理工艺研究

根据油田的使用经验,钻杆的失效主要体现在焊缝及内加厚过渡带两个部位.在提高焊缝的安全性方面,目前国内外各大钻杆生产厂主要是通过摩擦焊接方法及适当的焊缝热处理工艺来提高焊缝的安全系数.根据石油钻杆摩擦焊接及焊缝处理技术发展现状,结合API标准对石油钻杆焊缝力学性能的基本要求,对照中国石油天然气的行业标准,对宝钢生产的石油钻杆进行了部分焊缝力学性能统计,分析了宝钢石油钻杆的质量保证能力.为提高焊缝的安全系数,提出石油钻杆的摩擦焊接及焊缝热处理工艺的实现方法,并重点指出摩擦焊接与焊缝热处理工艺实现中应注意的问题.     

Development and Application of High Performance X80 Line Pipe for the 2^nd West-East Gas Pipeline

It is the development tendency of gas pipeline to improve strength of line pipe and transmission pressure, which is an important symbol of the progress of gas pipeline technology. The 2nd West-East Gas Pipeline (the 2 nd WEGP) is the largest-scale X80 high pressure gas pipeline project in the world. Through the joint development project by Pipeline Company, research institute, and steel company, a series of achievements of technology have been obtained, which makes it possible to apply pressure of 12 MPa and X80 LSAW and HSAW pipe for the 2 nd WEGP. Specifications of X80 steel and pipe have been issued based on API 5L. High performance X80 steel and pipe have been developed and meets the Specification. General design conception of applying HSAW pipe and LSAW pipe on gas transmission trunk line with large diameter and high pressure has been established. Failure control of the 2 nd WEGP has been carried out to avoid failure and reduce the lost which based on analysis of pipeline failure mode. In this paper, research and development of high performance X80 welded pipe, establishment of technical route of joint application of HSAW and LSAW steel pipe and key technology of failure control are emphatically discussed.     

宝钢UOE机组的装备水平与工艺技术

为满足中国石油、天然气能源输送管道建设需要大量高等级钢管的需求,宝钢分公司钢管厂兴建了一套现代化的大口径直缝埋弧焊管机组(UOE).该机组广泛采用了当今先进的UOE制造技术:大步幅的预弯边机、UO成型大压缩率控制、O成型的钢管中心恒定控制、O成型机的两段式变径液压缸、快速工具更换装置、数值分析模型等.同时概括介绍了该机组的产品方案,生产工艺、装备的技术参数和特点,并对采用的最新的C,U,O成型技术进行了论述.     

我国管道业发展对板带业的拉动

本文叙述了我国管道业面临的市场机遇和受到天然气价格等因素的制约以及进口钢管的挑战。建议中国管道业应适当发展ERW610机组和UOE机组的高质量产品；在钢板上宜以X70级为主，设备潜力可向X80级为目标而努力。     

宝钢不锈钢炼钢工程工艺创新实践

介绍宝钢不锈钢事业部不锈钢工程的工艺创新实践,论述了不锈钢冶炼工艺选择的依据,同时分析了宝钢不锈钢炼钢工程工艺创新的特点：第一次将不锈钢生产线和碳钢生产线布置在同一个主厂房内,采用了铁水罐喷吹脱磷工艺,为不锈钢生产线提供脱磷铁水,并设置了强搅拌型真空吹氧脱碳装置（SS-VOD）,在满足常规不锈钢冶炼需要的同时,也为宝钢生产超低碳、超低氮不锈钢以及超纯铁素体不锈钢创造了条件。     

Hydraulic Joint for Pipe Jacking

A newly developed hydraulic joint for pipe jacking is described and compared with conventional compression rings. It is shown that with the hydraulic joint, thrust eccentricities are largely reduced, resulting in a much more uniform stress profile at the pipe ends and hence a considerably reduced pipe damage potential. Higher jacking forces can be applied (fewer or no intermediate jacking stations are necessary), longer pipes can be used (fewer joints are necessary), smaller radii of curvature are feasible (fewer or no intermediate jacking pits are necessary) and frictional forces are reduced. The measurement of joint displacements and joint liquid pressures permits an effective real-time monitoring of the jacking process. 30 of the 40 pipelines with a total length of 8.2?km completed so far had curved alignments. The smallest radius of curvature was 86?m using 3?m long pipes with an internal diameter of 1.2?m. Practical experiences gained with the hydraulic joint are summarized.