奥氏体不锈钢埋弧焊拼排焊接试验

CFB(循环流化床)锅炉向大容量超临界参数发展是必然趋势,将会采用奥氏体不锈钢膜式管屏。奥氏体不锈钢膜式管屏的拼排工艺已引起业内人员的重视,针对奥氏体不锈钢的特点,采用埋弧焊工艺进行试验。为奥氏体不锈钢埋弧焊拼排选材及焊接工艺提供了依据,为今后更高等级的锅炉管屏埋弧焊焊接打下了基础。     

浅议热喷焊在锅炉膜式水冷壁中的应用

随着循环流化床锅炉的推广应用,膜式水冷壁管屏磨损问题日益突出,应用热喷焊技术对膜式壁管屏进行局部喷焊镍基合金,可以提高膜工水冷壁管屏的耐磨性,该文具体介绍了膜式水冷壁的喷焊技术。     

国内信息

上海锅炉厂新建的膜式水冷壁车间近日落成,这个面积达二万多平方米的车间,由40多台套设备组成了三条流水线,采用的是德国埋弧自动焊技术,可用国产光管加扁钢拼排生产锅炉膜式管屏,拼排管屏的最大宽     

T91管屏埋弧焊裂纹分析及焊接试验

介绍了T91钢用于炉膛膜式管屏的埋弧焊焊接过程中出现的典型裂纹,综合各种因素对裂纹的形成原理进行了分析.通过试验证实对于拘束应力大的T91管屏,埋弧焊拼排可通过多层焊获得合格的T91管屏.按此工艺生产多台CFB锅炉T91管屏,投运锅炉运行情况良好.     

700℃先进超超临界锅炉SA-213T92水冷壁埋弧拼排焊工艺研究

介绍了700℃先进超超临界锅炉膜式水冷壁候选用钢SA-213T92材料埋弧拼排焊的工艺性能,并通过多种焊接性、工艺性试验和模拟验证管排的埋弧拼排焊试验,了解SA-213T92埋弧拼排焊的焊接性和工艺性能,通过试验证实埋弧焊焊接工艺方法可用于SA-213T92膜式管排拼排制造。     

某电厂水冷壁绑带角焊缝开裂成因分析与对策

某电厂2号新建锅炉水冷壁在水压试验中发生泄漏,泄漏部位为水冷壁绑带角焊缝.通过样品管的分析检测以及施工过程检查对水冷壁绑带角焊缝开裂进行分析,认为水冷壁泄漏的原因为:北方冬季施工中未能严格执行焊前预热、焊后缓冷的焊接工艺,焊接温度偏低.通过优化设计,合理安排工期,严格执行焊接工艺,加强无损检测等措施,可以有效防范水冷壁绑带角焊缝开裂,提高受热面焊接质量.     

汽化炉封头与筒身内环缝埋弧焊应用

在石化容器的焊接生产过程中,埋弧自动焊以较高的焊接生产效率和稳定的焊接质量,得到了广泛的应用.本文介绍了在汽化炉的焊接生产中,通过对埋弧焊接设备的改造,实现了封头和筒身对接内环缝的埋弧焊接,提高了生产效率,降低了操作者的劳动强度,保证了焊接质量.     

集箱短管接头角焊缝埋弧焊工艺试验研究

为提高锅炉集箱短管角接接头焊接机械化程度及角焊缝质量,上海锅炉厂有限公司创新性地采用"内孔氩弧焊+埋弧焊"工艺方法,并与合作方联合开发"集箱短管接头角焊缝埋弧焊设备"。通过对高端材料、几种规格和不同坡口型式的短管接头进行的大量焊接试验,最终确定了最佳的坡口型式及焊接工艺规范参数,且获得了焊缝表面成型美观、接头质量可靠等性质优良的焊接接头,生产效率大大提升,为工厂生产应用和大面积推广打下了基础。     

膜式窄节距12Cr1MoVG管屏埋弧焊接试验及手工电弧焊补焊裂纹分析

12Cr1MoVG钢管制成的膜式管屏替代超临界锅炉折烟角SA213-T22管屏水冷壁的试验过程中,发现了埋弧焊角焊缝焊条电弧焊补焊裂纹缺陷.针对这一缺陷展开分析,并找到了缺陷产生的原因,同时提出了解决措施.从而为12Cr1MoVG钢管制成的膜式成排弯管屏应用于超临界锅炉产品奠定了基础,为进一步降低制造成本提出了有意义的探索.     

国内信息

最近,哈尔滨焊接研究所林尚杨等在国外单丝窄间隙埋弧焊的基础上,研制了双丝窄间隙埋弧焊工艺及设备,它是一种机——电——仪一体化的,全部自动化的新型埋弧焊设备。试验表明,它能明显提高焊接生产     

3D heat transfer model of hybrid laser Nd:Yag-MAG welding of S355 steel and experimental validation

A three-dimensional heat transfer model was developed to predict the temperature fields, the weld geometry and the shape of the solidified weld reinforcement surface during hybrid laser-MAG arc welding of fillet joints. Melt pool deformation due to arc pressure was calculated by minimizing the total surface energy. A series of hybrid welding experiments was conducted on S355 steel for different welding speeds and wire feeding rates. A high speed video camera was used to measure weld pool depression and surface weld pool geometry. Visualization of the weld pool during welding has also allowed for a better understanding of the interaction between the keyhole and droplets. The various weld bead shapes were explained through these observations. The arc pressure, the surface energy distribution, and arc efficiency were evaluated by comparing experimental data and numerical results for a wide range of welding operating parameters. Good correlation was found between the calculated and experimental weld bead shapes obtained for the hybrid laser-MAG arc welding process as well as for laser or MAG alone.     

Numerical Modeling of Cold Weld Formation and Improvement in Gmaw of Aluminum Alloys

Both mathematical modeling and experiments have been conducted on the formation of cold weld in gas metal arc welding (GMAW) of aluminum alloy 6005-T4. Transient weld pool shape and the distributions of temperature and velocity were calculated by a three-dimensional numerical model. The final weld bead shape and dimensions and peak temperature in the heat-affected zone (HAZ) were obtained. Three techniques were proposed to input more energy at the initial state of welding to improve weld bead penetration. Both the simulation and the experimental results show significantly improved weld bead penetration at the start of welding.     

核电管系的焊接自动化研究

核电再热管及辅助管系为公司重要生产部件,焊接量大,形状复杂,现多采用手工氩弧焊打底、半自动气保焊填充方法焊接,生产效率低、焊接质量不高。文章通过对产品结构分析,提出各自适合于再热管及辅助管系适合的自动焊方法,逐步实施,效果显著。     

Optimal parameters for pulsed gas tungsten arc welding in partially and fully penetrated weld pools

In the present paper, a numerical model of spot pulsed current GTA welding for partially and fully penetrated weld pools is presented. Heat transfer and fluid flow in the weld pool driven by the combination of electromagnetic force, buoyancy force, surface tension gradient and latent heat are included in our model. A new formulation of the electromagnetic problem is introduced to take into account eddy current in the weld pool. The shape of the free deformable surface under the action of pulsed arc force is also handled after the magneto-hydrodynamic calculation.The numerical model was applied to 304 stainless steel welding. We compare the influence of various pulsed welding parameters such as pulse frequency and current ratio on the weld quality. Experimental study is conducted to compare our numerical prediction with welding macrographies. It shows a good agreement of the model.     

Noncontact acoustic analysis monitoring of plasma arc welding

This paper addresses the problems involved in the automatic monitoring of the weld quality produced by plasma-arc keyhole welding. The acoustic signal of plasma arc welding was acquired by using a condenser microphone at high speed and analyzed with the aid of computers. It is shown that the overall AC power of the acoustic analysis, especially the low frequency part (0–100 Hz) of the acoustic signal power spectra, greatly varies with the variation of the statuses of the weld pool. A method for detecting the behaviours of the keyhole effect of plasma-arc welding was developed. The experimental results indicate that the method is a usable, practical one in the penetration quality monitoring of plasma-arc welding for on-line quality control.     

Analysing the influences of weld size on fatigue life prediction of FCAW cruciform joints by strain energy concept

The effect of weld size on fatigue life of flux cored arc welded (FCAW) cruciform joints containing lack of penetration (LOP) defect has been analysed by using the strain energy density factor (SEDF) concept. Moreover, new fracture mechanics equations have been developed to predict the fatigue life of the cruciform joints. Load carrying cruciform joints were fabricated from ASTM 517 ‘F’ grade steel. Fatigue crack growth experiments were carried out in a vertical pulsar (SCHENCK 200 kN capacity) with a frequency of 30 Hz under a constant amplitude loading (R=0). It was found that the crack growth rates were relatively lower in the larger welds fabricated by the multipass welding technique than the smaller welds fabricated by the single pass welding technique.     

GTAW liquid pool convections and the weld shape variations under helium gas shielding

The effect of the active element oxygen and the welding parameters (welding speed, welding current and electrode gap) on the liquid pool convections and the weld shape variations under helium gas shielding is systematically investigated using a mathematical model of the welding arc and weld pool during a moving GTAW of SUS304 stainless steel. Different welding parameters will change the temperature distribution on the pool surface, and affect the strength of the Marangoni convection and the weld shape. The inward convection induced by the electromagnetic force is contributive to the increase of the weld depth. A higher welding speed, lower welding current or larger electrode gap will make the weld D/W ratio decrease when the oxygen content in the weld pool is high. Under low oxygen content, a lower welding speed, welding current or shorter electrode gap will lead to a higher weld D/W ratio. The predicted weld D/W ratio by simulation agrees well with the experimental results.     

超级双相不锈钢S32750焊接工艺的探讨

通过试验证明,采用合理的焊接参数,严格控制层间温度及线能量,氩弧焊能保证超级双相不锈钢焊接接头具有合理的相比例,及良好的低温冲击韧性和耐点蚀性能.对实际生产具有指导作用.     

12Cr2MoWVTiB蛇形管的焊接技术

在深入分析了12Cr2MoWVTiB钢的成分特点以及其焊接性的基础上,以锅炉蛇形管12Cr2MoWVTiB钢为研究对象进行了焊接工艺试验,试验结果表明:采用手工钨极氩弧焊,选择直径为2.5 mm的H10Cr2MnMoWVTiB焊丝作为焊接材料,并且焊接时采用直流正接的方式,采用经试验确定的合理工艺参数焊接后得到了质量合格的焊接接头。     

0Cr18Ni10Ti与（SA387Gr11c12＋堆焊层）异种钢的焊接工艺

针对产品加强管（0Ci118Ni10Ti）与筒体（SA387Gr11C12＋堆焊层）角焊缝异种钢焊接接头焊接问题，提出了先在筒体开孔厚度上焊接隔离层，然后再焊接角焊缝实践证明，采用这种焊接工艺进行焊接，可以获得优良的焊缝，能够保证设备的正常运行、