焊接工艺对2205双相不锈钢焊接接头组织与性能的影响

采用等离子弧焊打底,分别用钨极氩弧焊盖面和熔化极氩弧焊盖面两种焊接工艺对2205双相不锈钢进行焊接,并对焊接接头进行了固溶处理。对采用两种焊接工艺的焊件的铁素体-奥氏体两相比例以及抗点腐蚀性能进行了分析和检测。结果表明,两种焊接工艺都可以满足焊接接头的各项性能技术要求,钨极氩弧焊焊盖面的焊接接头铁素体含量低于熔化极氩弧焊焊盖面,且冲击韧性也优于熔化极氩弧焊焊盖面,而熔化极氩弧焊焊盖面的焊接接头的抗点腐蚀性能优于钨极氩弧焊焊盖面。     

焊接工艺在承压设备中的运用

本文针对承压设备锅炉压力容器焊接产品不同的焊接型式,常用的四种焊接工艺方法：焊条电弧焊;非熔化极气体保护焊;埋弧自动焊;熔化极气体保护焊（主要指CO2气体保护焊）分别进行了阐述。介绍其工艺特点、适用范围、坡口型式、焊接参数等,为这四种焊接工艺在承压设备锅炉压力容器焊接生产中的应用,提供参考。     

焊接工艺 熔焊

弧焊和等离子弧复合焊接工艺过程，双电极焊条单弧焊的熔化特性 Ⅰ．双电极焊条的加热和熔化，双电极焊条单弧焊的熔化特性Ⅱ．电弧对二焊芯熔化的自调节作用，栓钉穿透焊焊接工艺研究，电容螺柱焊放电过程对焊接质量的影响，利用脉冲技术改善埋弧焊的焊缝成形质量。[编者按]     

不锈钢埋弧焊焊接特点研究

奥氏体不锈钢的物理特性与碳钢的差异较大，采用埋弧焊焊接不锈钢时，在同样的热输入下，不锈钢母材的熔化速度和对焊丝伸出端的预热作用比碳钢要大。在大量焊接试验的基础上，分析了不锈钢埋弧焊的特点，提出了不锈钢埋弧焊合理的焊接工艺，使不锈钢母材及焊丝的熔化速度和焊缝金属凝固速度平衡，从而避免了焊缝金属过烧和满溢，使不锈钢埋弧焊得到了广泛应用。     

正交试验法在高压钢管焊接工艺试验中的应用

在高压钢管熔化极气体保护焊的工艺试验中，采用正交法以较少的试验次数，较快而又准确地找到最佳的工艺参数，并收到了较好的效果。     

铝铜焊接进展

介绍了铝铜焊接的主要问题,评述了铝铜熔化焊、压力焊和钎焊等工艺应用概况。探讨了表面改性技术在铝铜钎焊中的应用。     

基于ODBC数据库技术的熔化极气保焊工艺参数控制技术的研究

介绍了采用Windows的ODBC数据库技术，利用面向对象程序设计（OOP）语言Visual C 设计的熔化极气保焊工艺参数控制（GWPC）系统。该系统实现了对焊接工艺参数的采集、存储、编辑功能，并具有一定的智能查询功能，同时，系统可对主要焊接工艺进行参数实时监控，从而实现高质量、高效率的自动熔化极焊接。     

熔化极气体保护焊焊缝成形的关键工艺条件

目前熔化极气体保护焊在广泛应用于很多行业,但由于缺乏系统全面介绍该焊接方法工艺的资料,同时熔化极气体保护焊工艺又较为复杂,导致不少多年从事熔化极气体保护焊的工作人员也很难将焊接工艺编制和焊接参数调节工作做得较圆满,阻碍了熔化极气体保护焊的应用与推广,因此研究总结熔化极气体保护焊工艺具有现实意义。在应用熔化极气体保护焊的基础上,用实验验证了焊接电流、电弧电压、干伸长度和焊接速度对焊缝成形的影响,分析总结了其对焊缝形状的影响规律,为熔化极气体保护焊技术的推广应用提供了技术参考。     

珠海市科盈焊接器材有限公司

日本“新日铁”气电立焊设备 气电立焊是由熔化极气体保护焊和电渣焊相结合发展而成的一种高效的焊接工艺，它利用类似于电渣焊所采用的水冷滑块挡住熔融的金属使之强迫成形，外加单一气体如CO2或混合气体如Ar＋O2作保护气体。在焊接电弧和熔滴过渡方面类似于熔化极气体保护焊，而在焊缝成形和机械系统方面又类似于电渣焊，同电渣焊相比熔化金属的热量是电弧焊而不是熔渣的电阻热，其能量密度比电渣焊高，且更加集中。其优点是焊缝一次成形而不需多道多层焊，生产率高、成本低。     

脉冲熔化极活性气体保护焊在不锈钢薄板中的应用

本文通过不锈钢薄板脉冲熔化极活性气体保护焊（MAG焊）焊接工艺评定试验，确定了不锈钢脉冲MAG焊各项工艺参数和操作，保证了产品的焊接质量，提高了生产效率。     

先进的搅拌摩擦焊

搅拌摩擦焊是利用一种特殊形式的搅拌头边旋转边前进，通过搅拌头与工件的摩擦产生热量，摩擦热使该部位金属处于热塑性状态，并在搅拌头的压力作用下从其前端向后部塑性流动，从而使待焊件压焊为一个整体。它可以焊接所有牌号的铝合金以及用熔焊方法难以焊接的材料，并突破了普通摩擦焊对轴类零件的限制。由于搅拌摩擦焊是固态焊接，所以没有熔化焊时的气孔、裂纹等缺陷。搅拌摩擦焊的接头性能普遍优于熔化焊的。     

Effect of pulse frequency in gas tungsten arc welding of powder metallurgical preforms

Abstract

Pulsing of the welding current is one approach for refining the fusion zone microstructure in materials joined by fusion welding. The effect of current pulse frequency on weld bead microstructure, tensile strength, and hardness in joining of powder metallurgical steel preform sheets to wrought copper was studied. Considering weld strength as the quality characteristic in the selection of process parameters, the Taguchi method is used to analyse the effect of each process parameter individually and of their interaction on weld strength, and subsequently to determine the process parameters leading to optimum weld strength. The application of pulsed current causes iron dendrites to become more equiaxed and uniformly distributed owing to dendrite fragmentation. Further, there was an optimum frequency range over which the microstructural refinement was maximal. The same optimum frequency range corresponded to maximum tensile strength. Enhanced fluid flow and reduced thermal gradients are thought to be responsible for refining the solidification structure and the resulting stronger welds.     

双丝间距对激光-双电弧复合焊接过程稳定性的影响

采用多信息融合技术对激光-双电弧脉冲复合焊在不同双丝间距下的电流信号、电压信号、高速摄像信号进行同步采集,研究双丝间距对焊接过程的电弧行为、熔滴过渡过程及焊缝表面成形的影响,并依据混沌理论和算法,从非线性角度对激光-双丝脉冲MIG焊接过程的电流信号进行了最大Lyapunov指数(LE)计算.结果表明,激光-双丝脉冲MIG焊接过程是一个混沌过程,由于激光光致等离子体和电弧等离子体的相互作用改变电弧的形态和熔滴受力状态,进而影响焊缝成形,在一定的焊接工艺参数下存在最佳双丝间距,在最佳双丝间距下,电弧稳定,焊缝成形良好,且此时最大LE值及其标准方差最小.     

异种材料的搅拌摩擦焊技术

进行了铝合金与工业纯铜、铝合金与低碳钢的搅拌摩擦焊接实验.实际焊接了对接接头、丁字接头、搭接接头,观察了焊接接头组织,测量了接头性能.结果表明,用搅拌摩擦焊方法代替熔化焊方法焊接异种材料,可以获得组织致密、无缺陷的接头,接头强度较高,且工艺适应性、结构适应性较好,焊接工艺参数、各组元在焊缝金属中的比例等对形成良好的焊缝有重要的影响.     

X70管线钢熔合区裂纹与焊接工艺的关系 孙咸

探讨了X70管线钢中熔合区裂纹与焊接工艺的关系。结果表明,在铁研试件中出现的沿熔合线分布的裂纹属于氢致冷裂纹。当冷裂纹三要素集中于X70管线钢熔合区的粗晶区时,该区成为接头的薄弱环节,极易形成裂纹。在裂纹影响因素中,熔合区组织特性是裂纹产生的必要条件,应力水平和氢的分布特征则是充分条件。焊接工艺与裂纹的关系实质上反映的是焊缝中氢和应力与裂纹间的关系。工程上常用焊缝中残留的扩散氢量最小化、不足以引发氢致冷裂纹的“焊缝金属低氢化”综合工艺,并获得了满意的效果。     

The humping phenomenon during high speed gas metal arc welding

Abstract

A commonly observed welding defect that characteristically occurs at high welding speeds is the periodic undulation of the weld bead profile, also known as humping. The occurrence of humping limits the range of usable welding speeds in most fusion welding processes and prevents further increases in productivity in a welding operation. At the present time, the physical mechanisms responsible for humping are not well understood. Thus, it is difficult to know how to suppress humping in order to achieve higher welding speeds. The objectives of this study were to identify and experimentally validate the physical mechanisms responsible for the humping phenomenon during high speed gas metal arc (GMA) welding of plain carbon steel. A LaserStrobe video imaging system was used to obtain video images of typical sequences of events during the formation of a hump. Based on these recorded video images, the strong momentum of the backward flow of molten metal in the weld pool that typically occurred during high speed welding was identified as the major factor responsible for the initiation of humping. Experiments with different process variables affecting the backward flow of molten weld metal were used to validate this hypothesis. These process variables included welding speed, welding position and shielding gas composition. The use of downhill welding positions and reactive shielding gases was found to suppress humping and to allow higher welding speeds by reducing the momentum of the backward flow of molten metal in the weld pool. This would suggest that any process variables or welding techniques that can dissipate or reduce the momentum of the backward flow of molten metal in the weld pool will facilitate higher welding speeds and productivity.     

奥氏体焊缝对中碳合金钢焊接裂纹的影响

采用奥氏体焊条焊接中碳合金钢时,发现了两种形态的裂纹:底层焊道中的热裂纹和熔合区裂纹。本文研究了焊条的合金系统、接头的显微组织以及底层焊道熔合区氢行为对裂纹的影响,探讨了裂纹的生成条件,并提高了有效防止裂纹发生的实用工艺。     

Study on fracture characteristic of welded high-density polyethylene pipe

Crack opening displacement (COD) was applied to characterize the fiacture initiation of the tough high density polyethylene. Normal single side notched three-point bend specimens and silica rubber replica techniques were used to study the characteristic COD of high-density polyethylene pipe and its butt-fusion joints including the weld fusion zone and heat affected zone at different temperature from - 78℃ to 20℃. Testing results show that the characteristic COD appears to depend on the structural features that are determined by welding process and the testing temperature. As the temperature is lowered, the characteristic COD of all zones studied decreases. Because the welding process significantly changes some structural feature of the material, characteristic COD of the weld fusion zone is the smallest one among those of the three zones. The results can be used for the engineering design and failure analysis Of HDPE pipe.     

热输入对6A02铝合金光纤激光焊缝成形的影响

采用大功率密度的光纤激光对1.0 mm厚的6A02铝合金进行了激光焊接,着重研究了焊接热输入对焊缝宏观形貌、组织和性能的影响. 结果表明,采用高速焊接且热输入控制在8～22 J/mm范围内可以获得稳定全熔透焊缝. 典型的光纤激光焊缝横截面常呈近X形,此种形貌的焊接温度场不均匀性较小,有利于减少焊接失稳和变形. 从熔合线至焊缝中心,显微组织逐渐从柱状晶组织向混合组织(柱状晶+等轴晶)转变. 随焊接热输入的降低,焊缝区的显微组织相对细化,接头熔合线附近的软化现象逐渐减弱,焊缝区显微硬度和接头抗拉强度均略有增加.