A6N01铝合金激光-MIG复合焊接接头工艺研究

激光电弧复合焊是一种低成本、高适应性的焊接方法,在铝合金、不锈钢等难焊金属中,可不同程度的减少和消除了焊接缺陷。以A6N01铝合金为研究对象,进行了焊接坡口设计,研究了间隙变化量对焊缝成形的影响以及进行了焊接接头残余应力检测。结果表明:为了满足激光-MIG复合焊接的工艺,需要设计单独的坡口型式。通过降低焊接速度,间隙为2.0 mm时仍可获得良好焊缝成形。MIG焊接,激光-单丝MIG焊接、激光-双丝MIG焊接,沿着焊缝的应力除个别区域外,皆为小于150MPa的压应力,激光-单丝MIG焊接的焊件整体应力值较小。     

铝合金激光焊接工艺特性

介绍铝合金激光焊接时的工艺特性及焊接难点 ,提出改进措施 ,讨论了焊接过程中裂缝、气孔出现的原因     

3A21铝合金激光焊与激光-氩弧焊复合焊微观组织及性能比较研究

采用激光焊接与激光-氩弧焊复合焊接2种方式对厚度为2mm的3A21铝合金板材进行对接焊,研究2种焊接方式下焊接接头微观组织、缺陷分布及硬度分布的不同。实验结果显示激光-氩弧复合焊接接头相比激光焊的接头显微组织更细密,且气孔数量明显减少。激光焊接接头的平均显微硬度与复合焊接头平均显微硬度相差不大,分别为52HV左右及51.3HV左右,均明显高于基体平均显微硬度值43HV。     

铝合金激光焊接的研究现状

综述了铝合金激光焊接技术的新近发展。列举了铝合金激光焊接的优越性和常见的焊接缺陷，重点分析了激光焊接气孔的复杂性和特殊性，给出了现今有关小孔研究工作的新进展。激光焊接的主要优点是高效率，尤其体现在大厚度的深熔焊接上。要想成功实现大厚度铝合金的深熔焊接，必须解决小孔所造成的气孔缺陷问题。     

YAG激光与GTAW复合焊接铝合金

研究了YAG激光、GTAW电弧复合焊接铝合金时各种规范参数对焊缝成型的影响规律 ,探讨激光与电弧的复合作用机理。结果表明 ,采用YAG激光 +GTAW复合工艺焊接铝合金具有焊缝成型美观、热影响区小等优点 ,与GTAW焊接相比 ,焊速显著提高 ,可以显著增加熔深 ,达到采用小功率激光焊机实现铝合金的焊接目的 ,Laser、GTAW是铝合金焊接理想的工艺方法。     

MIG复合焊接平台研制成功

由中科院福建物质结构研究所、漳州维德焊接技术开发有限公司和福建福晶科技股份有限公司承担的省科技重大专项专题“千瓦级全固态激光器的研究开发与应用”,近日通过福建省科技厅组织的专家验收。该专题瞄准先进制造产业需求,充分发挥各方优势,研制成功智能化激光MIG复合热源焊接平台。     

排布方式对铝合金激光-MIG复合横向焊接特性的影响

采用常规激光-熔化极惰性气体保护电弧(Metal inert gas,MIG)复合横向焊接铝合金过程中,焊缝表面极易出现咬边和下塌等缺陷,由此开展排布方式对激光-MIG电弧复合横向焊接铝合金焊接特性的影响研究。分析二者的排布方式对熔池特征、熔滴过渡形式以及焊缝成形规律的影响。试验结果表明,异面引导复合焊接方式对焊缝成形有明显改善作用,焊缝表面熔宽减少、中心线偏移和咬边缺陷得到有效抑制。采用同面引导复合方式时,熔滴过渡到匙孔后方,熔池下侧熔融金属大量堆积并产生周期性的波动,导致焊缝结晶组织出现了分层现象;而采用异面引导复合方式时,熔滴过渡到匙孔下方,并且熔滴在熔池中的落点位置与同面引导方式相比要偏上,熔滴过渡频率稍低,此时熔池中熔融金属分布较为均匀,熔池下部堆积金属较少,有效抑制了焊缝的下塌和咬边缺陷。     

高强度铝合金厚板的MIG—V焊接工艺研究

高强度铝合金厚板多层多道需射线探伤（RT）的焊缝形式,越来越多地被应用到高铁客车车体与车钩连接的部位。基于EN15085轨道车辆焊接质量管理体系的生产中,手工熔化极惰性气体保护焊（MIG-T）的不可靠性大大增加了检测及修理成本,机械化熔化极惰性气体保护焊（MIG-V）的众多优点使其替代MIG—T已成为趋势。     

基于激光——MIG复合热源的5A02铝合金/镀锌钢熔——钎焊

基于激光--MIG复合热源焊接技术实现了5A02铝合金/镀锌钢异种金属板材的优质、高效熔-钎焊接,并对焊缝的成形、接头性能及微观结构作了分析.分析结果表明,该焊接技术可以实现5A02铝合金/镀锌钢的高速熔-钎焊接,最高焊接速度可达5 m/min,焊接接头中镀锌钢母材未发生熔化,铝焊缝与镀锌钢母材为钎焊连接;焊接接头的抗拉强度可达153.1 Mpa,约为5A02铝合金母材抗拉强度的75.7%,接近于该铝合金熔化焊接头的强度;拉伸试验中试样断裂在焊缝铝合金母材热影响区,接头的断裂主要是塑性断裂,但有脆性断裂的痕迹.对接头的组织和结构进行分析表明:焊缝钎接界面处生成了一薄层Al-Fe金属间化合物,化合物层的平均厚度约为1.51μm,生成的金属间化合物主要为Fe3Al、FeAl2、Fe2A15、FeAl3,并且在这些化合物的周围会产生Si元素的富集.     

TC4钛合金精密焊接工艺研究

针对TC4钛合金,采用电子束焊接和激光束焊接两种方法,对焊深及其波动,焊接质量,焊接变形等方面进行了分析,获得了外观成型良好,色泽正常的焊接接头,经过X射线探伤,焊缝内部质量达到国际GB3233－87Ⅱ级要求,实现了TC4钛合金的精密焊接。     

铝合金脉冲GTAW焊熔池表面反射模型研究

熟练焊工能够通过观察熔池表面的凸凹信息获取熔池的成形,在机器人智能化焊接过程中,采用视觉传感方式模拟焊工视觉获取熔池的形状信息。图像的灰度值决定于光源特性、物体表面形状、反射特性和摄像机特性。熔池图像隐含熔池的形状信息,为了从图像中提取熔池的形状信息,分析了铝合金脉冲GTAW焊的熔池表面反射特性,熔池表面由漫反射表面、镜面反射表面和互反射表面组成,建立了熔池表面反射模型。     

焊接机器人在铝制板翅式散热器主焊缝焊接中的运用

介绍了焊接机器人在铝制板翅式散热器主焊缝焊接中的运用,通过优化焊接机器人焊接工艺,采用单层焊接替代手工TIG双层焊接,其单层焊熔深可达到4.0 mm~4.5 mm,单层焊时焊枪的焊速可达到350 mm/min~500mm/min,其焊缝爆破与压力交变强度满足铝制板翅式散热器主焊缝强度要求,焊缝外观成型良好,效率高,质量稳定可靠,同时也降低了工人的劳动强度。     

Laser vision sensing based on adaptive welding for aluminum alloy

A laser vision sensing based on the adaptive tungsten inert gas (TIG) welding system for large-scale aluminum alloy components was established to fit various weld groove conditions. A new type of laser vision sensor was used to precisely measure the weld groove. The joint geometry data, such as the bevel angle, the gap, the area, and the mismatch, etc., aided in assembling large-scale aerospace components before welding. They were also applied for automatic seam tracking, such as automatic torch transverse alignment and torch height adjustment in welding. An adaptive welding process was realized by automatically adjusting the wire feeding speed and the welding current according to the groove conditions. The process results in a good weld formation and high welding quality, which meet the requirements of related standards. Translated from Journal of Beijing University of Technology, 2006, 32(8): 714–718 [译自: 北京工业大学学报]     

TiNi形状记忆合金/钛合金异种材料激光焊

由于TiNi合金与钛合金的物理和化学性能差异较大,故其焊接性较差,焊缝区易形成大量的金属间化合物并产生裂纹。为实现上述材料的良好连接、提高接头性能,本文对采用激光焊连接0.2mm厚TiNi形状记忆合金和TC4钛合金异种材料进行了探索。分别采用直接对接焊和手工填丝焊的方法,研究了焊接接头的微观组织和力学性能。结果表明,直接对接焊时焊缝中心产生了纵向裂纹;手工填丝焊则通过合适的焊接工艺,改善了焊缝成形,避免了裂纹的产生。较优的焊接工艺参数为功率百分比18%、脉冲宽度3ms、脉冲频率3Hz;在界面区,Ni与TC4形成的过渡层宽度约为2μm,Ni与TiNi形成的过渡层宽度约为0.5μm。接头最大抗拉强度为332MPa,断裂位置发生在靠近TiNi侧的熔合线附近。     

铝合金表面激光沉积Al0.8FeCoNiCrCux高熵合金组织与耐蚀性能

为增强5XXX系铝合金表面的耐蚀性能,利用脉冲激光沉积技术制备了Al0.8FeCoNiCrCux高熵合金(HEA)涂层。利用XRD,SEM和电化学工作站分析了Al0.8FeCoNiCrCux高熵合金的相结构、微观组织和耐腐蚀性能。结果表明随着Cu含量增加,合金的相结构由BCC1和BCC2相转变为BCC1,BCC2和FCC相;当=0时,Al0.8FeCoNiCrCux涂层沿晶间出现裂纹,x=0.25时,涂层裂纹消失,并且在晶间出现了浅色组织,随着x增加,浅色组织由点状分布转变为连续生长;Al0.8FeCoNiCrCux(x=0.25,0.5,0.75,1.0)高熵合金涂层耐蚀性随Cu增加而降低,Al0.8FeCoNiCrCu0.25的腐蚀电流密为7.94×10^-8 A/cm^2,仅为基材的0.17%,腐蚀形式为点蚀,当x增加至1时,腐蚀电流密度增至8.21×10^-7 A/cm^2,为基材的1.99%,腐蚀形式转变为晶间腐蚀,但仍优于基材。显然,当0.25≤x≤1时,采用Al0.8FeCoNiCrCux涂层可显著改善铝合金的耐腐蚀性能。同时,其具有的高熵效应可抑制涂层中由基材的稀释行为引起的金属间化合物形成,解决了传统涂层材料应用在铝合金表面易产生裂纹的问题。     

铝合金MIG焊正面熔池图像视觉传感与处理

建立了铝合金脉冲MIG焊熔池图像检测CCD视觉传感系统。应用窄带滤光的方法成功地解决了强弧光干扰，通过大量试验，在获取清晰焊接熔池区图像的基础上，分析了铝合金焊接熔池图像的特征，研究了适合铝合金MIG焊熔池图像处理方法和熔池几何尺寸的边缘检出方法，获得了满意的熔池边缘特征图像，为进一步实现铝合金MIG焊接熔透智能控制奠定了基础。     

Study of mechanism of activating flux increasing weld penetration of AC A-TIG welding for aluminum alloy

When multi-component flux AF305 is used as surface activating flux for an aluminum alloy, the weld penetration of activating flux-tungsten inert-gas (A-TIG) welding is over two times more than that of conventional TIG welding. Using A-TIG welding with the modes of alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), respectively, the flux differently affects weld penetration when the polarity is different. After studied the effect of compelled arc constriction on weld penetration of AC welding, it is believed that the constriction of the whole arc root is not the main mechanism that flux AF305 dramatically improves weld penetration. The penetration has a relationship with the separate distribution of slag on the weld surface. Then, an observation of scanning electron microscopy (SEM) and an electronic data systems (EDS) analysis of slag were performed respectively. The separate distribution of slag on the weld pool during welding and the great constriction of arc spots were confirmed by TIG welding with helium shielding gas. The relationship between slag distribution and weld penetration was studied by adding aluminum powder into flux AF305 to change the distribution of slag. During welding, the separate distribution of slag on the weld pool results in the great constriction of arc spots, an increase in arc spot force, and an increase in Lorentz force within the arc and weld pool. Finally, the weld penetration is increased. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(5): 45–49 [译自: 机械工程学报]     

Effect of pulsed current welding on mechanical properties of high strength aluminum alloy

High strength aluminum alloys (Al-Zn-Mg-Cu alloys) have gathered wide acceptance in the fabrication of lightweight structures requiring high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength aluminum alloy are frequently the gas tungsten arc welding (GTAW) process and the gas metal arc welding (GMAW) process due to their comparatively easy applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results in inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying a pulsed current welding technique. Rolled plates of 6 mm thickness were used as the base material for preparing single pass welded joints. A single ‘V’ butt joint configuration was prepared for joining the plates. The filler metal used for joining the plates was AA 5356 (Al-5Mg (wt%)) grade aluminum alloy. Four different welding techniques were used to fabricate the joints: (1) continuous current GTAW (CCGTAW), (2) pulsed current GTAW (PCGTAW), (3) continuous current GMAW (CCGMAW) and (4) pulsed current GMAW (PCGMAW). Argon (99.99% pure) was used as the shielding gas. Tensile properties of the welded joints were evaluated by conducting tensile tests using a 100 kN electro-mechanical controlled universal testing machine. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Grain refinement is accompanied by an increase in tensile strength and tensile ductility.