钢结构焊接变形控制的理论研究

在钢结构的焊接过程中,由于焊接区域的局部收缩和应力作用将产生焊接变形,焊接变形会影响钢结构的尺寸精度、安装要求和施工进度。本文简要的阐述了焊接变形的控制方法和减小焊接应力的一些措施。选择合理的焊接顺序、采取反变形措施和对称焊接等几个方面可有效减小钢结构的焊接变形;从焊缝设计、焊接材料和焊接参数选择、焊接工艺布局、适当的热处理措施和振动时效处理五个方面来降低钢结构的焊接应力。     

钢结构焊接焊接应力、变形分析与控制

本文研究对象为焊接应力、焊接变形及控制,主要阐述存钢结构焊接施工过程中焊接应力和焊接变形产生原因及危害性,焊接变形种类,焊接应力与焊接变形控制措施,焊接应力消除与焊接变形的矫正方法。     

火电厂焊接施工质量控制探讨

在火电厂安装工程中,焊接是特殊的技术工种,施工范围主要有:锅炉受热面管子焊接,水、油、气管道焊接,承重钢结构和普通钢结构焊接,还有凝汽器钛管和铝母线焊接等。本文针对火电厂油管道焊接质量的控制,通过以往工程常见问题,从焊接材料、焊接人员、焊接环境等方面进行了分析。     

焊接过程宏微观数值模拟与仿真的研究现状

焊接过程的数值模拟与仿真是研究焊接热过程、焊接电弧行为、焊接熔池、焊接应力与变形、焊接结构疲劳与脆断、焊接接头力学性能、焊接接头微观组织、界面形成机理,以及焊接缺陷分析等问题的基础。借助计算机辅助技术对于焊接现象进行模拟研究,可以解决试验和实际生产中诸多的困难问题,对焊接过程控制和工艺优化等具有重要的指导价值。通过对目前国内外焊接领域关于焊接过程宏微观的数值模拟与仿真研究现状的分析,描述了焊接数值模拟技术的主要发展方向,并指出了一些研究中的热点问题,旨在为相关领域的研究工作者提供有效的帮助,开拓新的研究思路。     

轮式起重机吊臂筒体焊接变形分析及控制

目的 分析影响吊臂筒体焊接变形的因素及影响规律,从而找到吊臂筒体焊接变形的控制方法。方法 通过理论分析、数值计算、试验研究等手段,探讨吊臂经过摆搭、打底焊、焊接3道工序后,发生焊接变形的原因,得出焊接变形的控制方法。结果 轮式起重机吊臂的焊接,通过优化焊接工艺参数、焊接顺序及刚性固定,可以有效控制吊臂焊接变形。结论 对轮式起重机吊臂筒体摆搭、打底焊、盖面焊引起的焊接变形进行实物测量分析和有限元分析,然后根据分析结果得出,控制焊接变形的措施是有效的。     

要更加重视对新技术收集、总结、推广、宣传的工作

<正>最近参加中国安装协会焊接专业委员会2012年年会暨焊接标准及先进焊接技术研讨会,和协会会员单位以及相关企业总工程师、焊接技术负责人、质量技术负责人、焊接工程师、焊接技师等专业工作者,大专院校、科研院所的专家教授共同探讨先进焊接技术、提升安装行业竞争力的问题。会议归来,很有感受,很受启发。众所周知,焊接在安装行业中占据极其重要的地位。上个世纪七、八十年代,     

昆山华恒焊接 注重研发的焊接成套设备供应商

<正>昆山华恒焊接股份有限公司是我国焊接领域综合技术实力领先的自动化、智能化焊接成套装备的供应商、系统及工艺服务商,主要产品为焊接自动化成套装备(包括自动化管焊机、焊接专机)、工业焊接机器人和数字化逆变焊接电源。是目前行业中个别具备能研发生产组成自动化焊接系统的数字化电     

浅谈奥式体不锈钢的焊接质量缺陷及预防措施

奥氏体不锈钢广泛的应用在石油、化工、航空等工业中,具有良好的焊接性能,在焊接过程中也容易产生一些质量问题。本文分析了奥氏体不锈钢在焊接时焊接质量问题的原因,以及相应的缺陷预防措施。在实际焊接中只有熟悉并掌握奥氏体不锈钢焊接特点及焊接工艺,通过实践采用合理的焊接工艺措施和焊接环境,才可以焊接出完美的焊缝。     

船体结构钢焊接冷裂纹研究进展

对船体结构钢焊接冷裂纹研究进展进行了综述。分析了扩散氢、淬硬组织和拉应力等因素在焊接冷裂纹形成过程中的作用,介绍了基于3个影响因素形成的焊接冷裂纹形成机理,总结了基于焊接材料改进、焊接工艺控制、母材焊接性改进、低匹配焊接等思路的船体结构钢焊接冷裂纹控制方法,并对焊接冷裂纹研究重点进行了展望。     

浅谈安装工程中的焊接管理

焊接是建筑安装工程中的一个关键环节,焊接质量的控制管理工作贯穿于整个焊接过程。本文从焊接人员、材料、设备、过程、资料控制等几个方面阐述了焊接管理的内容及方法。     

双丝埋弧焊FCB法单面焊双面成形工艺研究

埋弧焊FCB法单面焊双面成形工艺在船厂已有大量应用,针对国内单面焊工艺应用现状和高强钢的特点研制了高强钢双丝埋弧焊单面焊工艺配套焊丝与焊剂,同时系统分析了焊接规范、坡口形式、背面焊剂对焊道成形的影响。通过调整工艺使其接头性能达到技术要求,该技术有望实现埋弧焊FCB法单面焊工艺的国产化应用。     

窄间隙焊接侧壁熔合控制技术的研究现状

窄间隙焊接因采用窄且深的U型或者I型坡口,在焊接厚板时具有焊接效率高、焊接填充量少及焊接变形少等诸多优势,在大型厚壁高强钢结构制造领域具有很好的应用前景。由于窄间隙焊接中电弧与坡口侧壁几乎平行,造成电弧无法对侧壁直接加热,易出现侧壁未熔合缺陷,严重影响了大型高强钢结构的服役安全。通过对窄间隙焊接技术研究现状的分析整理,综述并比较常用的侧壁熔合控制技术与方案,分析了其优缺点。分析结果表明,目前已经开发了旋转电弧、双电弧、带状电极、复合热源及摆动电弧等多种侧壁熔合控制技术,在一定程度上解决了侧壁未熔合问题,并且在压力容器、厚壁管道等领域获得了应用。最后对该方向的研究进展进行了总结,并对其发展方向进行了展望。     

Influence of the submerged arc welding in the mechanical behaviour of the P355NL1 steel—part II: analysis of the low/high cycle fatigue behaviours

A normalized fine grain carbon low alloy steel, P355NL1 (EN10028-3), intended for service in welded pressure vessels, where notch toughness is of high importance, has been investigated. Applications with this steel usually require the intensive use of welds. One of the most common welding processes that are used in the manufacturing of pressure vessels is the submerged arc welding. This welding process is often automated in order to perform the main seam welds of the body of the vessels. The influence of the automated submerged arc welding, in the mechanical performance, is investigated. In this paper (Part II) the low and high cycle fatigue and crack propagation behaviours are compared between the base and welded materials. Several series of small and smooth specimens as well as cracked specimens made of base, welded and heat affected materials, respectively, were fatigue tested. Strain, stress and energy based relations for fatigue life assessment, until crack initiation, are evaluated based on experimental results and compared between the base and welded materials. Finally, the fatigue crack propagation behaviours are compared between the base, welded and heat affected materials.     

Impact of welding research on steel composition development

A review has been made on development of technologies concerning welding and steel making and also on changes in requirements for structural integrity. The purpose is to understand how the development of welding technology has affected progress in steel making processes and especially that in chemical composition.     

不锈钢/钢复合管水压爆炸焊接制造的数值模拟

为研究水压爆炸焊接法制造不锈钢/钢复合管的焊接效果及炸药与复合管之间水层厚度对焊接的影响,对传统内爆法制备双金属复合管的工艺安装进行了优化,并利用有限元软件ANSYS/LS-DYNA建立了不锈钢/钢复合管水压爆炸焊接制造的二维有限元模型,对其焊接过程及变形情况进行了数值模拟研究.在模拟过程中得到复管与基管碰撞结合面节点的速度曲线和结合界面的压力曲线.结果表明:炸药与复管之间水层厚为1.5 cm时,模拟焊接过程中得到复管的最大飞行速度约453 m/s,基复管结合界面的压力约9.46 GPa,均满足爆炸焊接窗口理论计算值的下限要求,可以实现焊接;复管的最大飞行速度随水层厚度增加而减小,复管与基管有效焊接时间随水层厚度增加而增加;炸药与复管之间增加水层能有效地防止基、复管的大变形.水压爆炸焊接法为薄厚度、变形差等特殊材质双金属管的制造提供了一个重要的借鉴与参考.     

Using FEM to determine the thermo-mechanical stress in tube to tube–sheet joint for the SCC failure analysis

The stress corrosion cracking in a weld of the tube to tube–sheet region of heat exchangers is a common problem. Thermo-mechanical stress in tube to tube–sheet joints including welding effect should be determined in this situation for failure analysis. In this paper, the Finite Element Method (FEM) is used to predict the thermo-mechanical stresses including welding residual stress in a tube to tube–sheet weld. Both the thermo-mechanical stress distribution with and without the welding residual stress have also been investigated by numerical simulation. The welding, operating temperature, and operating pressure have effect on total stresses. Especially, the welding residual stresses play an important role in total stress state in tube to tube–sheet joints. Geometric discontinuities of the vicinity of gap cause the welding joint to experience a local stress concentration. A high tensile stress in the tube to tube–sheet region has been demonstrated by FEM, which is the stress aspect for the SCC phenomenon of austenitic stainless steel in chloride environment.     

Optimization of welding parameters for resistance spot welding of TRIP steel with response surface methodology

Many automotive companies are endeavouring to reduce the weight of the car body in response to various environmental issues. One initiative is the development of TRIP (Transformation Induced Plasticity) steels with a high strength and ductility. Resistance spot welding is a complex process, which requires specific optimal welding conditions based on experimental data. However, the trial-and-error method to determine the optimal conditions requires a large number of experiments, and so response surface methodology has been employed to overcome this problem. The second-order model was used here. This has been used in the resistance spot welding process of the TRIP steel and galvanized TRIP steel with a zinc-coated layer to optimize the welding parameters. The welding current, welding time, and welding force were selected as input variables, and the shear strength and indentation were selected as output variables.     

A335P91管道材料的焊接

由于P91钢具有良好的高温性能，近年来在我国的电力设备中得到了广泛应用，本文介绍P91管材的基本特征，焊接性能，焊接工艺及焊接质量检验，并阐述如何做好焊接质量控制。     

含稀土1Cr18Ni9Ti不锈钢焊接接头耐腐蚀性能的电化学研究

通过焊条药皮向１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢焊缝中过渡稀土,用高温电化学方法研究了稀土对焊缝耐内蒙古天然碱苛化烧碱腐蚀性能的影响。结果表明：采用适量的焊条药皮配方和焊接工艺可使稀土元素过渡到焊缝金属中,适量稀土元素改变了不锈钢焊接接头阳极极化曲线的极化度,从而改善了不锈钢材料焊接接头的耐蚀性。     

镀锌钢板点焊参数对熔核结晶形态的影响

分析和比较了普通冷轧钢板、电镀锌钢板和两种锌层厚度不同的热镀锌钢板在几种点焊参数下的熔核结晶形态。结果表明：镀锌层的存在对点焊熔核结晶形态很不利，增加焊接时间和焊接压力能使熔核结晶形态有所改善，但增加焊接电流会对其更不利。根据试验结果，对镀锌钢板点焊参数选择提出了建议。