耦合状态下激光对MIG焊熔滴过渡及焊缝成形的影响

采用高速摄影设备研究了CO2激光-MIG电弧复合焊接熔滴过渡的特点,试验结果显示在高速焊接时采用MIG焊的熔滴过渡特性比较复杂,是一种不稳定的混合过渡形式,当加入激光后由于激光光致等离子体对熔滴的热辐射作用和两个等离子体的耦合作用,熔滴过渡频率增加,熔滴过渡形式转变为一种单一稳定的射流过渡形式,电流电压恒定,焊缝成形良好,飞溅大大减少,熔宽熔深显著增加.因此采用激光-MIG复合焊接是一种高效率的新焊接工艺,具有广泛的应用前景.     

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.     

工艺参数对AZ31镁合金激光-MIG复合焊缝成形的影响

系统研究激光功率、电弧电流和热源间距对10 mm厚AZ31镁合金激光-MIG (Metal inert gas) 复合焊接工艺稳定性和焊缝成形的影响规律.结果表明:实现最大激光-电弧协同效应的最优热源间距为3 mm;复合焊接熔深决定于激光功率;MIG电弧电流对焊缝宽度有显著影响,但是对焊接熔深影响有限;在优化的工艺参数下,激光-MIG复合焊接能够有效消除镁合金激光焊缝中存在的表面成形缺陷,焊接速度提高50%;与MIG焊接相比,复合焊接熔深提高近10倍,电弧燃烧和熔滴过渡稳定性大幅度提高;因而激光-MIG复合焊接是镁合金焊接的一种有效方法.     

激光功率对激光-双丝脉冲MIG复合焊接电弧形态及熔滴过渡的影响

通过搭建激光-双丝脉冲MIG复合焊接系统,利用高速摄像与电信号采集系统对激光-双丝脉冲MIG复合焊接在不同激光功率下的电压电流信号及高速摄像信号进行同步采集,研究激光功率对焊接过程的电弧形态、熔滴过渡过程的影响.结果发现,由于激光等离子体与电弧等离子体的相互作用,电弧形态和熔滴受力状态发生改变.随着激光功率的增大,激光对电弧的吸引能力增强,促进熔滴过渡的等离子流力竖直向下的分力减小,熔滴过渡频率降低.     

CO_2激光-MAG电弧复合焊接工艺参数的优化

采用汉诺威分析仪和高速摄像机采集了CO2激光-MAG电弧复合焊接过程中的电信号和熔滴过渡图像,研究了焊接电流、电弧电压、激光功率等参数对复合焊接瞬时电压和电流信号、电压和电流概率密度分布、熔滴过渡特征和工艺稳定性的影响.结果表明,将汉诺威分析仪和高速相机相结合能提供丰富的焊接电弧物理指数和熔滴过渡形态信息,可为复合焊接...     

基于COMSOL的铝合金激光-MIG复合焊耦合作用研究

采用COMSOL软件对7A05铝合金激光-MIG复合焊焊接过程的电弧等离子体温度进行了数值模拟,并与实际焊接过程的高速摄影结果进行了比较。结果表明:在激光功率较高时,随着MIG电流的增加,作用区的温度波动较小;当激光功率达到一定程度后,再增加激光功率对作用区的温度场影响较小。当激光与电弧电极的热源间距为2mm时,在作用区上方的阴极区出现平台式温度,这对形成具有稳定流速和质量的熔滴状态具有重大意义。电弧电流200 A,功率3.5 k W,热源间距2 mm为较优的工艺参数,此时阴极电极附近出现温度平台区,作用区温度变化最小。     

CO_2激光-MAG电弧复合焊过程中激光功率对电弧及熔滴行为的影响

利用高速摄像系统和电弧分析仪分析CO2激光-MAG电弧复合焊过程中激光功率对电弧及熔滴行为的影响。试验结果表明:焊接过程中的实际热源间距受到焊接电流大小的影响,且当其在2 mm时焊接效果最优;在导电通道中的带电粒子在运动过程中扰动、漂移以及熔滴过渡模式、焊接模式的改变造成了焊接过程中电弧电流及电压波形的紊乱;激光功率影响了熔滴行为,当采用160 A和180 A的焊接电流时,激光功率的增加导致熔滴过渡频率先减小后增大。     

自保护药芯焊丝激光—电弧复合热源焊接电弧稳定性的分析

以自保护药芯焊丝（414N-O）为研究对象,借助电弧分析仪和高速摄像,对不同工艺参数下激光—电弧复合热源焊接电弧稳定性进行了试验研究.结果表明,复合热源焊接过程中,激光的加入明显的减小了自保护药芯焊丝电弧作用点漂移概率,拉长了电弧空间,降低了熔滴短路过渡概率,提高了电弧稳定性;工艺参数中,光丝间距和送丝速度对平均焊接电流影响显著;电弧电压和送丝速度对平均焊接电流变异系数影响显著;激光功率对平均焊接电流的影响幅度与光丝间距和送丝速度有关,光丝间距和送丝速度越大,激光功率对平均焊接电流的影响越小;电弧电压对平均焊接电流的影响幅度与光丝间距有关,光丝间距D_LA=0 mm时,影响最显著;激光前置比激光后置更有利于平均焊接电流变异系的稳定.     

等离子-MIG复合焊接熔滴过渡及电弧耦合特性研究

通过电信号采集系统和高速摄像采集系统对等离子-MIG复合焊接的电流信号、电压信号和熔滴过渡过程进行了同步采集,研究了等离子-MIG复合焊在不同焊接规范下最佳的熔滴过渡方式,对等离子电流对熔滴过渡的影响及复合焊接电弧耦合关系进行了分析。结果表明,等离子-MIG在不同焊接规范下均能实现良好的射滴过渡。在等离子-MIG复合焊接过程中,等离子电流对MIG焊的焊丝伸出长度和熔滴过渡有影响,随着等离子电流增加,MIG焊焊丝伸出长度逐渐缩短,直至由一脉一滴转化为一脉多滴;等离子弧与MIG弧相互耦合,MIG弧的加入使得等离子弧的电压升高,而等离子弧对MIG弧几乎没有影响。     

脉冲等离子-MIG复合焊熔滴过渡行为研究

将脉冲等离子电弧与MIG电弧同轴复合,期望利用等离子弧脉冲峰值电流产生的高速等离子射流冲击熔滴和熔池,促进熔滴过渡,同时增加焊缝熔深。开发了一套高速视觉与电信号精确同步的焊接数据采集系统,对脉冲等离子-MIG复合焊熔滴过渡行为进行研究。研究发现将等离子电流调制成脉冲波形,等离子弧对工件总体热输入下降,等离子峰值电流产生的等离子流力可以有效促进熔滴过渡。在此基础上深入分析了等离子脉冲峰值电流、脉冲宽度及熔滴在等离子弧过渡位置等参数对熔滴过渡的影响,获得了脉冲等离子-MIG复合焊一脉一滴过渡的工艺参数窗口。     

工业纯钛光纤激光-MIG复合焊接工艺及性能

采用光纤激光与熔化极惰性气体保护电弧焊(MIG焊)复合焊接工业纯钛,分别对激光焊、MIG焊和复合焊接头的焊缝表面成形、横断面进行了观察,并进行了激光焊和复合焊接头的拉伸试验及杯突试验.结果表明,复合焊的电弧稳定性比MIG焊显著提高,焊接速度可提高7倍;复合焊与激光焊接头的抗拉强度高于母材;复合焊接头的杯突值优于激光焊接头的杯突值,这是因为复合焊焊缝的微观组织有利于接头的塑性.因此,采用光纤激光-MIG电弧复合焊接方法很好地实现了工业纯钛的高速焊接,焊缝成形良好,接头的塑性优于单一激光焊的塑性.

Abstract：

Fiber laser-metal inert gas (MIG) arc hybrid welding was used to weld the commercial pure titanium (CP-Ti). The weld appearance, cross section, tensile strength, Erichsen value and microstructure of the CP-Ti welded joints were studied. The results show that the arc stability is substantially improved and the welding speed can be increased to 7 times by fiber laser-MIG hybrid welding. The welded joints by laser welding and the hybrid welding exhibit the higher ultimate tensile strength than those of the base metal. In addition, the welded joint by the fiber laser-MIG hybrid welding has higher Erichsen values than that by laser joints. The difference in plasticity is attributed to the microstructure changes in the welded joint of hybrid welding. Thus, the fiber laser-MIG hybrid welding of CP-Ti can be carried out suecessfully at higher welding speed with a good combination of weld bead appearance and plasticity.     

焊接参数对铝合金激光——MIG电弧复合焊缝熔深的影响

以5A06(LF6)铝合金为研究对象,研究了铝合金激光-MIG电弧复合焊(HYBRID焊)时焊接参数的变化对焊缝熔深的影响规律,并将焊接参数的变化对激光-MIG电弧复合焊、MIG电弧焊、激光焊的焊缝熔深的影响进行了综合比较分析.结果表明,若以等效于激光焊熔深的MIG电弧功率为分界线,可以把MIG电弧的功率分成高、低能量两个区,当激光与低能量电弧区的电弧复合时,激光对焊缝的熔深起主导作用,HYBRID焊的熔深大于该区的MIG电弧焊;当激光与高能量电弧区的电弧复合时,电弧对焊缝的熔深起主导作用,HYBRID焊缝主要体现为MIG焊缝的特点,加入激光的优势主要体现在增加焊接速度方面,即高速焊时也可获得良好的焊缝成形.     

铝合金激光-小功率脉冲MIG电弧复合热源焊接特性分析

针对5A06铝合金,通过一系列对比数据综合分析了MIG焊和激光MIG复合热源焊接技术在焊缝熔深、焊缝成形、焊接速度、焊接热输入等方面的优缺点.结果表明,在MIG平均电流小于200 A的小功率脉冲MIG电弧区域内,等热输入且等焊接速度条件下,激光-MIG复合热源焊接技术与MIG相比可以提高焊缝深宽比1～2倍,增加焊缝熔深0.43～2.5倍;等热输入且等平均焊接电流条件下,与MIG相比,激光MIG复合热源焊接技术可以提高焊接速度0.6～1.5倍,增加焊缝熔深0.5～5.9倍;激光MIG复合热源焊接技术可以用高于MIG焊0.6～6.5倍的焊接速度和更小的焊接热输入获得与MIG同样的焊缝熔深;与MIG焊相比,激光MIG复合热源焊缝的铺展性更好,更适合于高速焊接;MIG复合2 kW的激光能量后会增加平均电弧电压、减小平均电流.     

Study of laser MIG hybrid welded AZ31 magnesium alloy

Abstract

The laser metal inert gas (MIG) hybrid welded AZ31 magnesium alloy is discussed in weld shape, microstructure characteristics and mechanical properties in comparison of single laser and arc welding. The stable MIG arc, reliable droplet transfer and regular weld that are hardly obtained in single MIG welding can be obtained in hybrid welding by laser arc synergic effects. The ultimate tensile strength and elongation of hybrid weld are far higher than those of laser weld and reach 97·8 and 87·5% of base metal respectively. Under this experimental condition, the efficiency of hybrid welding is 1·20 times faster than that of single laser welding. Between the wide upper part (arc zone) and the narrow lower part (laser zone), obvious difference is observed. Arc zone has coarser grain size and wider partial melted zone than laser zone. Finally, the porosity reduction mechanism of hybrid weld is discussed according to the weld pool shape and the acting forces on it.     

激光-MIG电弧的复合作用及对熔滴过渡的影响

试验研究激光与MIG电弧的相互影响与相互作用,以及激光的加入对MIG电弧形态与熔滴过渡形式的影响.搭建了YAG激光-脉冲MIG电弧复合焊接试验系统,进行了焊接试验并同步采集了焊接过程中的电信号和高速摄像图片信号.通过分析电信号和高速摄像图片可以发现,对于一脉一滴的焊接过程,加入激光后熔滴过渡形式由一脉一滴变为两脉一滴过...     

Process and joint characterizations of laser-MIG hybrid welding of AZ31 magnesium alloy

High power laser-metal inert gas (MIG) hybrid welding of AZ31 Mg alloys was studied. Microstructure and fracture surface of welded joints were observed by optical microscope and scanning electron microscope. The mechanical properties of welded joints were evaluated by tensile test. Under the optimal welding parameters, the stable process and sound joints were obtained. The tensile strength efficiency of welded joints recovered 84-98% of the substrate. It was found that the arc was compressed and stabilized by the laser beam during the hybrid welding. The compressed extent of arc column increased with laser power, and the process stability could be improved by increasing laser power and arc current or slowing welding speed. The arc stabilized mechanism in laser-MIG hybrid welding of Mg alloys was summarized in two factors. First, the laser keyhole fixes the arc root and improves the igniting ability of the arc. Second, the electromagnetic force is downward and increased by the laser-arc interaction, which prevents the overheating of the droplet and smoothes droplet transfer from the wire to the weld pool.     

激光-MIG复合热源铝合金层间堆积快速成形

在铝合金熔化极惰性气体保护焊快速成形过程中,由于焊接热输入量大、电弧稳定性差等因素,层间堆积时易产生熔池外溢、坍塌等成形缺陷.应用低功率激光-MIG复合热源焊接工艺,以两种不同的层间堆积方式形成了铝合金单道多层墙体零件.并对零件的表面质量、金相组织以及显微硬度进行了分析.最后用该工艺在无支撑条件下形成了40°的斜面墙体零件.结果表明,与常规MIG焊相比,低功率激光-MIG复合热源焊接工艺能够对铝合金层间堆积过程进行更加精确稳定的控制,且零件组织更加均匀.     

Mathematical analysis of the role of recoil pressure in weld pool dynamics during laser-MIG hybrid welding

A mathematical model was established to simulate the weld pool development and dynamic process in stationary laser-MIG hybrid welding. Surface tension and buoyancy were considered to calculate liquid metal flow patter, moreover, typical phenomena of MIG welding, such as filler droplets impinging weld pool, electromagnetic force in the weld pool, and typical phenomena of laser beam welding, such as recoil pressure, Inverse Bremsstrahlung absorption, Fresnel absorption were all considered in the model. The laser beam and arc couple effect were introduced into this model by the plasma width during hybrid welding. The role of recoil pressure in the weld formation was discussed. Transient weld pool shape and complicated liquid metal velocity distribution from two kinds weld pool to an unified weld pool were calculated. The simulated weld bead geometry with consideration recoil pressure was in good agreement with experimental measurement.     

YAG激光与脉冲MIG复合焊接

研究了YAG(掺钕钇铝石榴石 ,Nd 3:Y3Al5O1 2 )激光与脉冲MIG电弧复合焊接铝合金的新工艺 ,设计制造了复合焊接机头 ,探讨了各种规范参数对焊缝成形的影响规律及激光与电弧的复合作用。结果表明 ,在比较宽的参数范围内YAG激光 -脉冲MIG复合焊接铝合金焊缝成形美观 ,无气孔等缺陷 ,熔深与激光单独焊比增加 4倍 ,与脉冲MIG焊接比增加 1倍以上 ,焊速显著提高 ,是一种理想的焊接工艺。