双面螺旋埋弧焊钢管的交流消磁.pdf

双面螺旋埋弧焊钢管的交流消磁 唐彦林 翁继红 宝鸡石油钢管有限责任公司 摘 要 介绍了双面螺旋埋弧焊钢管交流消磁的原理及系统构成,有效地消除了钢管剩 磁对X光工业电视检测的影响,且满足标准对管端剩磁的要求。 关键字 埋弧焊 焊接钢管 交流消磁 剩磁 0 前 言 双面螺旋埋弧焊钢管SAW在焊接过程中, 内焊采用直流焊接方式,内焊大线和焊头部位因 大电流,产生较强磁场,钢管管体在该磁场作用 下,磁矩获得或趋向于获得与外磁场相同方向的 排列。当焊接结束,磁场逐步减少直至消失时,因 磁滞现象,在管体上还有剩余磁通密度存在,这就 是我们通常所说的剩磁现象。剩磁的存在,使图 像增强器的电子束方向偏转,X光工业电视系统 图像产生 “S” 型扭曲变形如图1示 , 影响气孔、 夹渣等自然缺陷,特别是未焊透、 裂纹等线状自然 缺陷的检出率。随着管线钢级的提高及X光电 视系统图像增强器的换型,剩磁的影响尤为突出。 且剩磁的存在,在管线环焊对接时,会产生偏弧现 象,影响焊接质量。G B/ T9711. 2及API Spec 5L 42 版标准均对钢管剩磁提出了明确要求。在 2001年,我们初步采用对钢管施加反向磁场的直 流消磁法,由于我单位 个分厂有两条生产线,两 条生产线所生产钢管及同一钢管管头和管尾剩磁 差异较大,直流消磁装置难以使两个机组生产的 钢管剩磁状态消除到理想状态,且返修管二次经 过消磁工位,会形成充磁现象,使管体剩磁加大。 经进一步研究,笔者提出了采用交流法消磁 方案。 图1 受剩磁影响扭曲变形的工业电视图像 1 交流消磁的原理 使钢管以运动状态通过一交变磁场,从圆形 线圈内轴线方向的磁感应强度公式1可知,管体 的任一截面上各点受交变磁场作用的磁感应强度 相关于通过线圈的瞬时电流、 线圈半径及匝数等 参数。如图2 B - H磁滞回线所示aba′b′a为饱 和磁滞回线 , om为管体剩磁形成曲线剩磁 ≥ b1 , 调整线圈电流,使消磁磁场的强度幅值大于 或等于m点所对应的磁场强度Hm,随着电流由 大到小变化,磁场强度从Hmϖ0 ,0ϖ-Hc1, -Hc1 ϖ-Hm1 - Hm1 -Hm , - Hm1ϖ0 ,0ϖHc1′, Hc1′ ϖHm变化,相应的管体任一截面上各点的磁 感应强度将分别沿着曲线mϖb1, b1ϖc1, c1ϖ m1, m1ϖb1′, b1′ ϖc1′, c1′ ϖm变化其中c1, c1′ 磁感应强度为0, m , m1和b1, b1′ 磁感应强度大小 相等,方向相反 , 形成闭合曲线。随着钢管的运 动,任一截面上各点到磁场区的距离变远,其所受 图2 B - H磁滞回线 34焊管 第27卷第4期2004年7月 磁场强度幅值逐渐减小,形成如图m′b2c2m2b2′ c2′m′ 所示的更小的磁滞回线,剩磁值从b1ϖb2, 逐步减小,依次类推 ⋯,电流和磁场强度趋近于 零,剩磁值亦趋近于零。通过以上过程,管体磁畴 排列方向将被打乱,管体材料可达到退磁状态。 B μnI 2R 1 式中 μ 为磁介质的磁导率; n 线圈匝数; I 为瞬时电流; R 线圈半径。 2 交流消磁装置的构成 钢管交流消磁装置如图3示,用350 A左右 的交流电焊机作为消磁线圈的供电电源,因交流 消磁所需消耗电能较大,为确保线圈及时散热,线 圈制作材料选用铜排间断工作。在线圈进管侧置 一光电位置检测开关。用自动消磁方式,当钢管 管头到达该位置时,自动启动消磁装置,对钢管自 动消磁,直到钢管管尾离开光电开关检测区延时 图3 钢管交流消磁示意图 约3 s之后,自动关闭消磁装置,一根钢管的消磁 过程结束,整个消磁装置回到待机状态。 3 结束语 钢管交流消磁法,经实际使用,可将管端剩磁 消到1 mT以下,消除了管端剩磁对X光工业电视 检验系统的影响消磁后的图像如图4所示 , 满 足G B/ T9711.2及API Spec 5L42版标准对剩磁 的要求,且构造简单、 操作方便,易推广应用。 图4 消磁后的工业电视图像 参考文献 1 王以真.实用磁路设计.天津天津科学技术出版社, 1992 2 程守洙,江之永.普通物理学.北京高等教育出版社, 1982 第一作者 唐彦林,男,1964年生,工程师, 1989年毕业于西安石油大学电子仪器与测量技 术专业,现在宝鸡石油钢管有限责任公司从事无 损技术工作。联系电话0917 - 3398727 E2mail tangyanlin1 sina. com 收稿日期2004 - 01 - 20 编辑 罗 刚 我国天然气工业将全领域对外开放 中国石油天然气集团公司经济技术研究中心副主任 刘克雨日前表示,根据目前天然气发展战略与政策,我国 政府鼓励外商参与从事天然气勘探开发、 基础设施、 天然 气发电站、 大中城市燃气等项目的建设与经营,对外开放 的领域几乎涵盖了整个天然气产业链。 在天然气勘探开发领域,目前我国天然气已经形成 的气区主要集中在海上和西部地区。资源探明储量低、 发现潜力大,同时勘探开发难度大、 技术水平要求高。加 快天然气勘探开发不仅需要加大资金,也需要加快引进 国外先进的勘探开发技术和先进的管理经验。 在天然气管线、 液化天然气等基础设施建设方面,有 关方面预测,在2002～2020年间,我国天然气基础设施建 设共需投资2200多亿元。主要用于建设5万km的天然 气管线,千万吨规模的液化天然气接收站和百万吨规模 的液化天然气运输能力。 在天然气终端销售领域,天然气长输管道的建设高 潮即将带来终端销售市场的投资高潮。 在天然气发电领域,将给国外设备制造商创造更多 机会。目前发电在天然气消费中的比重大体占14 ,今 后这一比例将上升到30 以上。对老电厂进行改造扩建 及对现有燃气机组进行燃气改造,都会创造商业机会。 在煤层气的开发利用上,国外投资和先进技术也大 有用武之地。刘克雨认为,我国天然气领域拥有诱人的 投资前景,未来会成为中外合作最活跃的领域之一。 摘自中国石油网2004年6月21日消息 44焊 管 2004年7月 Lining Plastic to Supplying Pipe and Pipe Fittings Qian Lezhong21 AbstractIt introduces the structure ,perance ,material ,ap2 pliance scope and implementing standard of lining plastic to sup2 plying water pipe and fittings. It also analyses characteristics of lining plastic compound pipe and lining stainless steel pipe ,put forward lining polyethylene or thinner wall2thickness stainless steel pipe to inside wall of outside layer pipe ,thus it not only greatly enhance the pipe anti2corrosion property during transmit2 ting water ,hot water and coal gas ,but also retain the advantages of galvanized pipe ,such as sealing better with thread connection , high physical stress and low price. It will be ideal substitution for transmitting water and gas pipe. Key words lining plastic supplying water compound pipe pipe fittings Flexible Control Technique of Digital2control Flying Saw System Tong Zihui26 Abstract This paper introduces flexible control principle of digi2 tal control flying saw ,analyses its flexible control technique in all move section of one sawperiod. In DFPLC - I type control sys2 tem,firstly positive start2up accelerated speed will be conducted auto2calculate and auto2adjusted inside position loop. In order to protect driving system and mechanic and avoid over2accelerated speed ,accelerated speed regulation loop is attached to behind po2 sition loop ,but not alter curve slope outputted by position loop. Adopting sectional accelerated speed liner increase achieve in2 flexion smooth transition of saw liner accelerated speed ,to reduce impact value.Using special design flexible control technique ,ef2 fectively reduce saw physical impact and abrasion. It is a very practical control technique for frequent start2up and stop of digital control flying saw. Key words digital control flying saw flexible control control principle Over2evaporating Cooling Electric Tube and Its Application in High2frequency Heat Field Dai Zhengwu29 AbstractThe over - evaporating cooling electronic tube adopt anodic cooling technology. Its efficiency is 10 times that of com2 mon water cooling electronic tube. It also makes brief introduction to over2evaporating cooling electronic tube applied in high2fre2 quency welded pipe machine in domestic and abroad. Key words electronic tube over2evaporating cooling high2fre2 quency power welded pipe application Using AUTOCAD 2002 Develop Cold2bend Sectional Pipe2 hole Design Software Zou Junliang33 AbstractIt describes using VISUAL BASIC6. 0 matched with AUTOCAD 2002 connection ,and adopting VB program to deal with AUTOCAD 2002 figures. It introduce three foundational functions of self2developing pin2hole design software K ongXing2 T ools1.0 . Key words cold2bend sectional steel pin2hole design VISU2 AL BASIC AUTOCAD 2002 connection Application of Welded Pipe Roller CAD/ CAPP Technology Li Hui35 Abstract The quality of roller directly effect welded pipe quali2 ty. With the series size of welded pipe development ,it put forward higher requirements for roller design. On basis of CAD and CAPP ,we research and develop one set of design program system for welded pipe roller. This paper introduce us function and pa2 rameter design of program system. With its application ,it can greatly lighten manpower’s work. And enhance design effi2 ciency and quality. Key words roller CAD/ CAPP parameters design welded pipe Characteristic of Steel Pipe Lining Plastic and Its Familiar Quality Problems Settlement Liu Huiyi37 Abstract The procedure of steel pipe lining plastic is to plastic pipe extrude out and coating bond on its outside surface , and then insert into steel pipe inside. Through heating ,pressuring and cooling sizing process ,the plastic pipe is integrated with steel pipe firmly. It introduce equipment properties ,procedure parame2 ters and quality standards ,as well as familiar quality problems during production. It all gives solving s for these prob2 lems. Key words steel pipe lining plastic procedure of plastic pipe standard quality defects solving Improve Service Flying Saw Cut Accuracy Zhang Yuhua , Chai Xiaoyan40 Abstract It describe two approaches for improving service flying saw cut accuracy. They are improving attendant system operation model and improving organ of flying saw driving.After improved , the cut accuracy of service flying saw is higher than international custom standards. At present ,it is widely applied in actual pro2 duction. Key words service flying saw saw cut accuracy approach organ Intercourse Removing Magnetism of SSAW Pipe Tang Yanlin , Weng Jihong43 Abstract It introduce us principle for intercourse removing mag2 netism and system structure of SSAW pipe. It can effectively re2 move steel pipe residual magnetism ,which can effect x - ray in2 spection on steel pipe. Thus ,it can reach the standard require2 ment for pipe ends residual magnetism. Key words SAW welded pipe intercourse removing magnetism residual magnetism Design for sway2style hydraulic edge smashing machine Zhang Xinfang 45 Abstract It is very important to mill strip edges during SSAW pipe production ,which can directly effect work line continuous production. It analyzed on - line shearing style and different posi2 tion disposal feature ,which is used in most pipe manufacturer. It raised a newly and practice sway2style hydraulic pressure smash2 ing strip edges manner. It also describe newly device structure character and its design essential point. It is valuable to use wise2 ly. Key words SSAW pipe disc shearing strip bar smashing machine Discussion on Reclaiming SSAW Pipe Inside Welding Slag Li Jun, Wang Zhitai , Wang Airu47 Abstract It introduce me many means of reclaiming inside weld2 ing slag of SSAW Pipe. It analyzed their advantages and disad2 vantages. It mainly describe induced air engine sucking welding slag and welding flux. This set of device has the operation sim2 ple ,cost low and repair easy ,as well as enlighten labour tension , enhance the safety of welded pipe production. It is a good refer2 57 第27卷第4期 英 文 摘 要