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 hotinduction-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 fieldconstruction applications.     

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.     

珠江钢管公司在发展中崛起

叙述了珠江钢管公司发展UOE焊管的市场背景，以UOE工艺流程和X70级为代表的“西气东输”钢管的冶金工业水平，从而折射出这家公司在发展中崛起。     

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.     

关于宝钢建设UOE钢管生产线若干技术问题探讨

论述了世界UOE机组发展概况，分析了钢管直径、壁厚、钢级等主要参数，评述了工艺流程及设备主要组成，比较了UOE与SSAW、JCOE等方法的力学原理，提出了引进UOE机组的原则。     

对螺旋缝高频焊钢管机组技术改造的实践

对我公司原螺旋缝高频焊钢管的工艺流程和螺旋缝埋弧焊钢管的生产工艺流程进行了比较、分析和研究，提出了对螺旋缝高频焊钢管机组进行技改的总体方案，实施了技术改造，使该机组实现了螺旋缝高频和埋弧焊钢管双功能生产的要求。     

Arc welding of annular seams under flux in high-strength X80 steel pipe

The relation between the content of martensitic-austenitic phase and the final temperature in accelerated cooling is investigated, in terms of the attainment of high deformability without failure. The ratio of the yield point to the strength (Y/T) in the longitudinal direction (L) of X80 steel pipe produced by UOE technology is found to be between 0.74–0.79. This indicates good deformability of the pipe. A welding technology has been developed such that the metal in the seam matches the strength of the X80 steel pipe. In industrial flexure tests, when the internal pressure is 72% of the standard yield point (SMYS) of X80 steel, the failure of X80 steel pipe welded by the given technology occurs in the basic metal, far from the annular weld.     

焊接钢管高频感应加热的残余应力和组织演变

 随着中国钢铁、冶金与电磁等交叉学科的快速发展,焊接钢管产量及质量日益提升。高频感应加热是生产焊接钢管的核心工序,获取更加精确的焊管高频加热过程的应力分布和微观组织演化规律,是进一步提升焊管品质的关键要素和学者们关切的问题。综合考虑热传导和微观组织转变对应力的影响,针对高频焊管特有的沙漏形热源形貌,定量分析了焊接热影响区微观组织演变过程和残余应力的分布规律,获得了考虑热应力和组织应力的残余应力分布。发现该应力特点为在焊缝附近轴向残余应力较大,最大等效残余应力出现在距焊缝中心1/2壁厚处的热影响区,在壁厚方向管材内部的中间层的残余应力较大,且应力分布与反映高频焊接热源形貌特征的加热温度峰值和加热温度宽度相关。而在焊缝中心处,未考虑组织变化的等效残余应力值是考虑组织变化的1.3倍。掌握焊管高频焊接应力和组织演变的特点和规律,可为优化高频焊接工艺提供理论依据,对提升高频焊管质量具有重要意义。     

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.     

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.     

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.     

特殊加载条件下X65管线管焊缝SSCC的试验

 采用4点弯曲试样,对X65钢级UOE焊管焊缝接头进行NACE0177标准规定的SSCC（Sulfur Stress Corrosion Cracking,硫化物应力腐蚀开裂）试验,并采用应变计法完成目标应力加载。结果表明,通过应变计法可以有效地建立FPB（Four Point Bent,4点弯曲）试样加载应变-载荷-应力关系,并根据该关系准确确定目标加载应变量,从而实现目标应力的准确加载。采用该方法完成试验试样90%实际屈服强度的应力加载,并经H2S环境溶液浸泡720h后表面未见裂纹,试验材料表现出优异的抗硫化物应力腐蚀开裂性能。     

Numerical simulation of the UOE forming process based on MSC. Marc secondary development technology

U-ing-O-ing-Expanding (UOE),the main process for making longitudinal submerged arc welded pipe(LSAW) with steel plate,is famous for its superior quality and reliability.Based on the famous non-linear finite element analysis (FEA) software MSC.Marc,a finite element model (FEM) has been established to simulate the whole UOE forming process by using the secondary development technology with the Python language.Research has also been conducted systematically on the crimping,U-ing,O-ing and mechanical expanding processes.The practice has shown that the simulation calculation is in close conformity with the actual site production data.The FEM has been successfully applied in the UOE production at Baosteel.     

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.     

Bending Behavior of Steel Pipe Girders Filled with Ultralight Mortar

Bending behavior of steel pipes filled with ultralight mortar was studied by bending tests using a steel pipe, steel pipes filled with ultralight mortar, and steel pipes filled with light aggregate concrete and normal concrete. The steel pipe model filled with normal concrete had 1.8 times higher bending strength than the steel pipe model. The bending behavior of the steel pipe filled model with ultralight mortar was not improved when the compressive strength of the ultralight mortar was less than 1 MPa. However, ductility was much improved when the compressive strength was over 5 MPa, and the ultimate steel strain was more than double of the steel pipe model. The strains of steel and concrete in all the models were proportional to the distance from the neutral axis until the steel plate yielded. A simple analytical method was proposed to calculate the bending moments of the ultralight mortar filled steel pipes. The calculated values agreed very well with the test results.     

Practice and reflection of Baosteel longitudinal UOE submerged arc welding technologies self-reliance integrated innovation

The capability of self-reliance integrated innovation is one of the key factors that influence steel enterprise’ s core competitiveness.The main equipments of Baoteel UOE unit are from abroad,but the key consistent pipe manufacturing technologies including iron making,steel making,heavy plates are self-reliance integrated.The self-reliance integrated innovation of Baosteel UOE unit has the features of high challenge, high efficiency,high starting point,consistent technologies etc.The independent innovation capacity achieved by adjusting measures to local conditions and periods in introducing projects is the key to the development of continuing robust.Baosteel longitudinal UOE submerged arc welding tube project practice also offer beneficial reference for independent of integration innovation.     

高频直缝焊管焊接和热处理研究进展

 焊接钢管在石油化工、电力工业、农业灌溉和城市管网建设等领域得到了广泛的应用。随着高频焊管越来越多地应用于条件恶劣的工作场合，保证焊缝质量也成为业内关注的重点。为了揭示该学科的发展现状以及发展趋势，结合国内外研究现状，从温度场、残余应力、组织和力学性能3个方面介绍了高频直缝焊接及热处理以及其对焊缝质量的影响。当前高频直缝焊接技术研究的局限性在于难以建立适应性更强的多参数综合数学模型。高频直缝焊接技术未来的发展方向是高精度、智能化。     

高强度汽车传动轴管的开发与应用

采用超细晶化的高强度钢板,开发和研制高强度汽车传动轴管,可以极大地提高轴管的屈服强度．使之在承受较大扭矩的情况下确保汽车安全行驶,既能使车身轻量化以利降耗节能,又提高了陆路物流的周转速度。这种新产品的开发,是焊管行业科研攻关的一个重大课题。我们追踪世界同行业的科研动向,通过优化成型与焊接工艺确保轴管的焊接质量达到国际先进水平。填补了国内ERW高强度汽车传动轴管方面的空白。取得了明显的经济效益和社会效益。     

翻转内衬技术在煤气管修复工程上的应用

煤气管网随着运行时间的增加，易发生煤气泄漏，引发各种事故。利用翻转内衬软管技术，修复并延长旧管网的使用寿命，经济，技术，安全等性能良好。     

Total Friction Loss along Multiple Outlets Pipes with Open End

This paper describes the derivation of the total direct and relative reduction factors for both discrete and continuous outflow along mixed service sections of close end multiple outlets pipes. Discrete outflow factors depend on the numbers of outlets along the section and the entire pipeline, while for continuous distribution there is no such dependence. Solutions for close end pipes are also derived. The total relative factors are related to those previously calculated total factors for close end pipes. The concept of “effectiveness” is presented here for close and open end pipes by taking into account the friction loss occurred downstream of the first outlet, resulting in both head and flow variation between that upstream outlet and the remaining outlets along the line. The dependence upon the extremity spacing is also considered. There are also proposed formulations for mixed factors for intermediate sections between two locations along a close end pipe.