Characteristic of laser-MIG hybrid welding with filling additional cold wire for aluminum alloy

The weld appearance, deposition rate, welding efficiency, stability of arc, laser keyhole characteristic, and weld property were studied by using a novel laser-MIG hybrid welding process with filling wire of aluminum alloy. The results were also compared with those by conventional laser-MIG hybrid welding process. It was found that with the suitable process parameters this novel welding process for aluminum alloy was stable and final weld bead had fine appearance. Compared to conventional laser-MIG hybrid welding process, during this novel welding process the stability of arc, the laser keyhole characteristic and the weld property were similar, while the keyhole cycle frequency and keyhole opening area had differences of 1.23% and 15.34%, respectively, and the welding efficiency increased by about 31% without increasing heat input.

Joint performance in laser welding Al alloy with filler wire

CO2 laser welding aluminum alloy with filler wire was studied. The results indicate that the problems in CO2 laser welding of Al alloy, such as bad appearance of weld, easily excessive penetration and low strength, can be improved effectively by using laser welding with filler wire, and the maximum tensile strength of weld can reach 94% for the base metal. It also can be found that, the linear energy have great influence on the microstructure and mechanical properties of the joint. As the heat input increases, the cellular fir-tree crystals in the weld zone become sparse and the form of tensile fracture transforms from gliding fracture to brittle fracture.

国产ER 5356与ER 5087铝合金焊丝焊接接头在盐雾环境下的腐蚀行为研究

对国产ER 5356和ER 5087铝合金焊丝焊接接头进行0~1000 h的盐雾腐蚀试验,试验周期分别为100 h、250 h、500 h、750 h、1000 h。用质量法和标准数对其进行评定,并用扫描电子显微镜SEM观察两种焊丝焊接接头焊缝、焊接热影响区及母材中性盐雾腐蚀试验后的微观形貌。结果表明:腐蚀时间短时,失重率急剧上升,100 h时失重率达到最大;随着腐蚀时间继续延长,失重率逐渐减少,750 h后失重率趋于稳定。国产ER 5356和ER 5087铝合金焊丝焊接接头的平均失重速率分别为0.0051~0.0186 g/m^(2)h和0.0050~0.0103 g/m^(2)h,其腐蚀面均达到9.5级以上;两种铝合金焊丝焊接接头的焊缝、焊接热影响区和母材的微观形貌均变化不大。

Effect of Conventional and Pulsed TIG Welding on Microstructural and Mechanical Characteristics of AA 6082-T6 Repair Welds

Repair welding of AA 6082-T6 joints was carried out using ER 4043 filler through the TIG welding process with or without pulsed current.Microstructure and mechanical characteristics of the joints before and after repairing were investigated by examining macrostructure,microstructure,and distributions of porosity in the weld metal(WM),and by hardness,tensile,and bending tests.We observed that the welding current,phase transformations in heat-affected zone(HAZ)and porosity introduced in the WM during welding influence on its mechanical properties in sequence.The experimental results showed that the bead width and penetration as well as size of pores in the joints were mainly influenced by the welding currents.The sound joints were obtained at a welding current of 140 A with or without pulsed current when welding speed and gas flow rate were set at 20 cm·min-1 and 15 L·min-1,respectively.Among them,the decrease in mechanical properties of repair weld(RW)was directly related to the phase transformations in the over-ageing zone due to the double welding thermal cycles and elevated distribution of porosity in the WM.In addition,it was observed that the comparatively smaller grain size and lower porosity in WM of the RW produced by pulsed TIG welding gave a positive effect on its mechanical properties.

Al-Mg-Mn-Er-Zr合金激光焊接接头的疲劳性能

研究了Al-Mg-Mn-Er-Zr合金薄板及其激光焊接接头的静态拉伸性能和疲劳性能,并获得相应的S-N曲线及条件疲劳极限.通过微观组织分析及疲劳断口观察,探讨了Al-Mg-Mn-Er-Zr合金激光焊接接头的疲劳断裂原因.结果表明,Al-Mg-Mn-Er-Zr合金激光焊接接头存在明显的组织不均匀性,母材为典型的轧制组织,焊缝区的显微组织为细小等轴晶,晶粒尺寸约为40μm,热影响区为再结晶组织;激光焊接接头的抗拉强度低于母材,存在焊接接头软化的现象,接头系数约为0.73;激光焊接接头的条件疲劳极限为母材合金的68.5%;焊接接头的组织不均匀性及焊缝中的第二相夹杂是影响接头疲劳性能的主要原因.

Fe对ER5356焊丝熔敷金属腐蚀性能影响

选择3.5%NaCl溶液浸泡腐蚀试验方法,采用扫描电镜观察分析腐蚀形貌和Image Pro Plus软件定量统计腐蚀面积率,研究了Fe对ER5356焊丝熔敷金属耐腐蚀性能的影响。结果表明,熔敷金属腐蚀微观形貌呈点蚀特征,点蚀坑在第二相周围萌生,点蚀机理为阳极溶解;随着焊丝中Fe元素含量的增加,熔敷金属点蚀坑面积率呈线性增加。

ER5356铝合金焊丝力学性能与PLC效应分析

对冷变形态ER5356铝合金焊丝进行不同的退火工艺处理,采用室温拉伸试验研究了退火工艺对铝合金焊丝力学性能和PLC效应的影响。结果表明,中间退火时间为1 h时,退火温度由300℃升高到400℃,铝合金焊丝PLC效应减弱,当经过350℃×1 h退火时,冷拔铝合金焊丝抗拉强度为316 MPa,断后伸长率为22%,PLC效应相对较弱;低温退火温度大于200℃时,成品焊丝会出现反常PLC效应,造成塑性变形不均匀,当经（100~200）℃×1 h的低温退火时,成品焊丝残余应力降低,强度塑性匹配良好。

真空中间退火拉拔制备ER5356焊丝MIG焊接头的组织与性能

在铝合金焊丝拉拔制备过程中,采用真空退火工艺对每道次拉拔后的焊丝进行中间退火处理,然后采用MIG焊接方法和制备的ER5356铝合金焊丝焊接20 mm厚7A52铝合金板,并对焊接接头的组织与性能进行研究。结果表明:采用真空中间退火工艺制备的ER5356铝合金焊丝,焊缝质量达到I级;与大气中间退火制备的焊丝相比,焊缝组织形态和晶粒大小变化较小;真空中间退火制备的焊丝焊接接头力学性能优于大气中间退火制备的焊丝,接头平均抗拉强度为293MPa,平均断后伸长率为5.5%,接头拉伸断裂机制为韧性断裂。

微量Sc、Zr和Er对5182铝合金焊缝组织与性能的影响

在ER5356铝合金焊丝中添加了微量的Sc、Zr和Er,制备出微合金化ER5356铝合金焊丝.使用微合金化焊丝焊接4 mm厚的5182铝合金板材,焊接采用手工钨极惰性气体保护焊.利用金相显微镜,X射线衍射以及透射电镜研究了微量的Sc、Zr和Er对5182铝合金焊缝处显微组织的影响.结果表明,在ER5356铝合金焊丝中添加的Sc、Zr和Er可以有效改善5182铝合金板材焊后焊缝处的显微组织,显著细化组织晶粒.其中,ER5356铝合金焊丝中单独添加0.3%Sc焊后效果最佳.

不同焊丝对Al-6Mg-0.7Mn-0.2Er-0.12Zr合金板材焊接性能的影响

分别以ER5E61、ER5B71铝合金焊丝为填充材料,采用脉冲TIG焊接方法对4 mm厚的Al-6Mg-0.7Mn-0.2Er-0.12Zr合金板材进行对接焊接试验,对比两种铝合金焊丝焊接接头的显微组织和力学性能。结果表明:当焊接电流为140 A时,两种焊丝均可实现单面焊双面成形。采用ER5E61铝合金焊丝焊接,焊接接头的屈服强度为177 MPa,抗拉强度为335 MPa,伸长率为12.15%,焊接系数为87%;采用ER5B71铝合金焊丝焊接,焊接接头的屈服强度为182 MPa,抗拉强度为343 MPa,伸长率为14.11%,焊接系数为90%。由于ER5B71铝合金焊丝中复合添加的Sc、Zr元素进入焊缝组织中,析出的Al_(3)(Sc, Zr)粒子的晶格类型及晶格常数与铝基体的极为相似,错配度极小,当焊丝熔化进入焊缝时,起到了较好的晶粒细化效果,提高了焊接接头的强度。

Microstructures of 2219 twin wire welded joints

With thick plates of 2219 high-strength alloy, the microstructures of welded joints with twin wire MIG welding were analyzed. Experimental results show that no hot crack was found in the weld due to discontinuous distribution of cocrystallization with low melting temperature, but porosity is serious in the first weld seam that is mainly composed of equiaxial grains with uneven sizes. As the poor position of the whole welded joint, fusion zone has big and coarse grains, uneven microstructures ; In quenching zone, there exist a lot of soaked microstructures that cocrystallizntion with low melting temperature solute into matrix, thus strengthening the metal in this zone; In excessive aging zone, much more phases that distribute evenly will be separated from the matrix; Ontside this zone, properties and microstructures of the metal are basically similar to matrix due to the relatively low temperature or unaffected heat in the zone during welding.

生产ER5356铝合金焊丝用连铸连轧杆原料的热塑性

以进口生产ER5356铝合金焊丝用连铸连轧杆原料为研究对象,采用高温拉伸试验研究了不同温度(250~550℃)下连铸连轧杆的高温强度、塑性变化规律,并观察了断口形貌,得到最佳热塑性温度区间。结果表明:随着温度升高,该连铸连轧杆的高温强度呈单指数降低趋势,断后伸长率增大,断面收缩率变化不大,说明该连铸连轧杆具有较好的高温塑性;随着温度升高,晶界弱化,沿晶断裂区域面积增加,拉伸断口形貌由韧窝变为韧窝+脆性沿晶断裂混合形貌,最后完全变为脆性沿晶断裂形貌;ER5356铝合金连铸连轧杆的最佳热塑性温度区间为375~525℃。

不同Mn含量及焊接电流对ER5356铝合金焊丝焊接性能的影响

为研究不同Mn含量ER5356铝合金焊丝和焊接电流对焊接焊头性能的影响,实验使用含锰量为0.05%和0.15%的ER5356铝合金焊丝,分别在110,115和125 A焊接电流下,采用TIG焊接6082铝合金.结果表明:用ER5356(0.15%的Mn)铝合金焊丝焊接得到的焊接接头的性能整体优于ER5356(0.05%的Mn)焊丝焊接得到的焊接接头,因Mn元素可以改善焊接接头的力学性能,进而提高铝合金焊接质量;随着焊接电流的增大,焊缝成形质量提高,当焊接电流为125 A时,无焊接热裂纹等宏观缺陷,焊接接头断口几乎观察不到未焊透的现象,焊接接头匹配系数最高达到0.71.

国内外5087铝合金焊丝焊接接头组织及力学性能的对比

分别对进口ML5087和国产ER5087铝合金焊丝采用熔化极惰性气体保护焊进行平板对接工艺试验,并对其焊接接头进行了拉伸、弯曲试验、硬度测试及宏观微观金相观察。结果表明:进口与国产铝合金焊丝焊接接头的强度系数分别为0.79和0.82,且侧弯试验结果合格,故均具有良好的拉伸、弯曲性能;2种铝合金焊丝焊接接头的硬度分布相近,热影响区的硬度与焊缝的相当,均低于母材硬度。2种接头焊缝熔敷金属均呈铸态,其成分基本相近,熔合区近焊缝处为柱状晶组织,热影响区出现了成分偏析的现象,晶粒较为粗大。

7075与ER5356铝合金焊丝用于7075铝合金MIG焊接头性能对比研究

采用MIG焊的方式使用自制7075铝合金焊丝与市面购进的ER5356焊丝进行3mm厚7075铝合金对接焊,对比分析两种焊丝焊接接头的显微组织与力学性能。经过光学显微镜(OM)、X射线衍射(XRD)、扫描电镜(SEM)与能谱仪(EDS)结合室温拉伸与显微硬度测试,结果表明:两种接头焊缝组织均为枝晶网状组织,但由于合金元素含量与热导量增大,7075接头焊缝组织相对细小且枝晶特征更为明显。SEM和XRD检测分析得出,由于焊接时金属流动作用将部分母材合金元素带至焊缝,两者焊缝析出相均主要为η相(MgZn_(2))、S相(CuMgAl_(2))或T相(AlZnMgCu),同时存在Al_(13)Fe_(4)金属化合物。7075焊缝平均硬度为120HV,相较于5356焊缝更为优异;两者拉伸力学性能较为接近,断裂机制相同。

5183高端铝合金焊材生产技术开发

通过研究5183高端铝合金焊材生产工艺,确定合金成分、开发熔体深度净化工艺和退火工艺,同时还开发出直接用电解铝液连续铸造-热连轧-冷连轧的短流程、低能耗的5183铝合金焊材生产技术,建成国内首套电解铝液连续铸造-热连轧-冷连轧铝合金焊丝线坯生产线,焊丝线坯最小尺寸达到直径2 mm。

铝合金焊丝送丝稳定性测试分析

【目的】旨在深入分析影响4043铝合金焊丝送丝稳定性的因素,为铝合金焊丝产品质量检测提供指导依据。【方法】选取市面上国内外常用的5种4043铝合金焊丝,提取焊接过程中的送丝阻力、送丝速度,以及焊丝表面质量和焊丝拉伸性能等关键参数,综合分析评价送丝性能。【结果】通过测试送丝阻力和焊接时送丝速度的波动情况,得出不同厂家的铝合金焊丝在焊接过程中送丝阻力值、送丝速度的波动幅度区别较大;通过对铝合金焊丝表面质量观察分析,可以发现焊丝表面的微观形貌状态是影响送丝稳定的主要因素,焊丝表面平整度高、表面划痕少可以有效保证送丝稳定性;通过对铝合金焊丝拉伸性能测试和微观拉伸断口扫描分析可知,焊丝内部气孔少且小可以保证焊丝的拉伸性能,同时提高铝合金焊丝送丝稳定性。【结论】通过提取焊接过程送丝阻力和焊接时送丝速度的标准方差,可以客观评价4043铝合金焊丝的送丝性能,并与实际情况相符合;焊丝表面平整度高、微观划痕少的焊丝送丝性能良好,因此,为提高4043铝合金焊丝送丝稳定性,必须严格控制焊丝拉拔或刮削工艺;焊丝内部缺陷少的焊丝送丝性能良好,因此,为提高4043铝合金焊丝送丝稳定性,必须严格控制焊丝冶炼工艺。

焊丝成分对5454-H32铝合金焊缝组织与性能的影响

以使用脉冲弧熔化极气体保护焊焊接的3.2 mm厚5454-H32铝合金对接接头为研究对象,使用光学显微镜、SEM、EDS和显微硬度计,分析2种接头的显微组织、析出相形态、分布和成分及显微硬度,测试接头的力学性能。分析结果表明,使用ER5356焊丝焊接的接头各项性能均优于使用ER4043焊丝焊接的接头性能。

乘用车车门铝板材料激光填丝焊试验研究

以乘用车铝合金车门为研究对象,通过仿真模拟与工艺试验的综合应用,研究铝合金板材的激光填丝焊工艺和焊接质量,通过评判焊接后焊缝的成形质量和力学性能等,获得适用于铝合金车门激光填丝焊的最佳工艺参数,并利用此参数进行铝车门内板总成的激光填丝焊试制,获得了较好的焊接质量。结果表明,针对厚度为1.5 mm的5182铝板和6016铝板激光填丝搭接焊,采用激光功率为2600 W、焊接速度为2.5 m/min、送丝速度为7 m/min的参数配置,可获得较好的焊缝成形质量和力学性能,满足实际铝车门内板总成的焊接质量要求。

Dendritic Boundary Corrosion of AA2198 Weld Using Fiber Laser Welding with Al–Cu Filler Wire

The microstructures and corrosion behaviors of AA2198-T851 alloy and weld were analyzed under corrosive conditions. Weld was formed using an innovative fiber laser welding process with AA2319 Al-Cu filler wire. The metallurgic morphology and distribution of the chemical compositions were determined using imaging techniques such as optical micrograph, scanning electron micrograph, high-resolution transmission electron microscopy, energy-dispersive X-ray spectrometry and X-ray diffraction. Corrosion was evaluated using an immersion test and electrochemical impedance spectroscopy in 3.5% NaC1 solution at room temperature. Results indicate that the parent alloy suffered from pitting corrosion during the initial 4-h immersion which was caused by the inhomogeneous distribution of its chemical compo- nents and the different intermetallics formed during the rolling process. The weld experienced dendritic boundary corrosion under the same conditions due to the addition of the Al-Cu filler and rapid solidification during laser welding, which led to the precipitates Cu enrichment along the grain boundary. When a welding joint was immersed in the solution for 5 days, a big crack was observed across the center of the weld. In comparison, there was good corrosion resistance in the heat- affected zone with a compact protective film.