共查询到19条相似文献,搜索用时 140 毫秒
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CO2气保护药芯焊丝熔滴行为对药芯焊丝工艺性有直接的影响,不同的熔滴行为可间接反映在焊接过程电信号的变化中.利用汉诺威弧焊分析仪对CO2气保护药芯焊丝的焊接电参数进行测试分析,提取短路大电流概率密度和、短路过渡频率、瞬时短路频率以及瞬时短路时间和等与药芯焊丝工艺性紧密相联的4个特征信息.然后,采用主成分分析法确定药芯焊丝工艺性评价指数,对药芯焊丝工艺性进行定量化评价,从而为科学评价药芯焊丝工艺性提供了新方法. 相似文献
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钛型渣系气保护药芯焊丝熔滴过渡及其控制 总被引:3,自引:0,他引:3
孙咸 《机械工人(热加工)》2005,(5):26-29
从熔滴过渡形态及分类、过渡形态与工艺性关系、熔滴过渡机理、熔滴过渡影响因素及控制等方面.探讨了钛型渣系气保护药芯焊丝熔滴过渡及其控制原理。结果表明.该焊丝熔滴过渡的基本形态是非轴向滴状过渡.在电弧电压较纸瞬时,亦会发生短路过渡行为这类焊丝熔滴过渡形态对工艺性的影响,取决于焊接规范参数的变化.主要是焊接电流.并通过影响熔滴过渡指数.进而使工艺性指标发生之,依据该焊丝熔滴形成过程特点,建立了药芯焊丝熔滴过渡受力模型,焊接电流变化时.不同的作用力对熔滴过渡起主要作用。通过调整药芯组成物,选择焊丝截面形状,改变焊丝直径和钢带厚度.优化焊接工艺参数.改变作用于熔滴上相关力的大小或方向.最终实现对熔滴过渡的控制。 相似文献
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孙咸 《机械工人(热加工)》2014,(6)
分析了GMAW熔滴过渡形态,重点探讨了钛型渣系CO2气体保护药芯焊丝的电弧、熔滴过渡特性,并以工程应用实例论证该类焊丝熔滴主流过渡形态。结果表明,GMAW用焊丝的工艺质量很大程度取决于熔滴过渡形态和电弧行为。熔化极气体保护电弧焊主要熔滴过渡形态是滴状过渡、短路过渡和喷射过渡。钛型渣系CO2气体保护药芯焊丝的电弧形态应属于活动、连续型,在大电流、强规范(含高的电弧电压)条件下施焊时,该焊丝熔滴主流过渡形态是非轴向滴状过渡。 相似文献
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基于脉冲GMA电弧检测了电弧填丝增材制造过程中与熔滴过渡相关的电弧电流、电弧电压和声发射信号,研究了电弧脉冲作用下的铝合金熔滴射滴过渡特征,提出了一种可对处于射滴过渡模式下的熔滴尺寸、电弧力和熔滴沉积率进行计算的方法,并分析了沉积层的成形质量特征。研究结果表明,利用检测获得的电弧电压、电弧电流信号和声发射信号可以对处于射滴过渡模式下的熔滴过渡过程及其特征进行区分。在本研究条件下,作用在过渡熔滴上的电弧力随电弧功率增加而递增。电弧力的增加将限制熔滴尺寸的增大,从而在电弧功率递增时呈现熔滴尺寸的递减和熔滴过渡频率的递增。同时,电弧功率增加,使热输入增大,射滴过渡熔滴对熔池的冲击增强,容易造成熔滴过渡形成的沉积层坍塌,从而使熔滴沉积层高度递增的趋势减缓,形成的沉积层显微组织明显粗化。 相似文献
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随着逆变焊机的发展和数字技术的应用,逆变CO2气体保护焊电源可通过调节焊接电源输出的电流与电压来控制熔滴过渡,改善焊缝成形,降低飞溅.根据熔滴过渡不同阶段的要求产生电流与电压控制信号,进行波形控制可实现调节短路电流上升速度,以减小短路峰值电流,降低短路爆炸能量;减少瞬时短路的次数;通过短路后期液桥颈缩电压上升率切断短路电流,消除电爆炸能量.以此有效减少CO2气体保护焊短路过渡产生的飞溅量,为低飞溅CO2气体保护焊的设计与实现提供有力保证. 相似文献
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采用自制熔滴收集装置、高速摄影仪、电弧焊质量分析仪研究了在电流小于100A条件下焊接时焊缝金属中硅锰质量比对E308LT0-1不锈钢药芯焊丝熔滴过渡及电弧稳定性的影响。结果表明:随着焊缝金属中硅锰质量比的增大,焊接过程中大尺寸熔滴占比先降后增,小尺寸熔滴占比先增后降,当硅锰质量比为0.311时,小尺寸熔滴占比最大,大尺寸熔滴占比几乎最小;不锈钢药芯焊丝的熔滴过渡形式主要为非轴向短路过渡,当硅锰质量比为0.311时,熔滴过渡最平稳,飞溅程度最低,电弧稳定性最好。 相似文献
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短路过渡CO2焊接熔滴形状数值模拟与控制 总被引:2,自引:0,他引:2
为了进一步提高短路过渡CO2气体保护电弧焊的工艺性能和焊接质量,根据高速CCD摄像获得的熔滴及其短路过渡图像,分析了熔滴与熔池短路前的形状对熔滴与熔池的短路、熔滴在熔池中的铺展及液桥缩颈形成的影响.采用熔滴静力平衡模型研究了电磁力(燃弧电流)、表面张力、重力与熔滴形状的关系,并通过对燃弧电流的精确控制实现了对熔滴形状的有效控制.当熔滴与熔池短路前为细长形状时,短路过渡过程稳定柔顺,而当熔滴为扁平形状时,则不利于熔滴的短路过渡,甚至产生瞬时短路.燃弧阶段的熔滴形状体现了各种力对熔滴的作用,而电磁力(燃弧电流)是决定熔滴形状的主要因素.根据燃弧电流对熔滴形状的影响规律,提出了采用前期大、后期小的燃弧电流控制原则,以在燃弧的不同阶段获得不同的熔滴形状.试验结果表明该控制方法获得了良好的适合于熔滴短路过渡的短路前熔滴形状,短路过渡过程柔顺稳定,消除了瞬时短路以及由此导致的飞溅,改善了熔滴的短路过渡行为,短路过渡结束后焊丝端部的残余液态金属具有良好的一致性. 相似文献
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冷金属过渡(CMT)电弧增材制造技术具有沉积效率高、制造成本低等优势,在航空用大尺寸构件的快速成型领域应用前景广阔。对于电弧增材制造大型构件需采用大电流来进一步提高沉积效率,但在此高电流模式下电弧放电过程对熔滴过渡行为的影响机理尚不明确。因此,本研究采用高速摄像仪观察了电弧增材制造过程中电弧形态及熔滴过渡行为,同时通过建立电弧模型及熔滴过渡模型,分析了在不同电流波段及工艺参数下熔滴过渡频率及熔滴尺寸变化规律,最终揭示了电弧放电过程中电流密度、洛伦兹力等物理因素对熔滴过渡的作用机理。结果表明,电弧宽度与洛伦兹力决定熔滴在电弧放电过程中的受力大小,进而决定熔滴尺寸及其过渡频率。随着送丝速度从5.5 m/min增大至7.0 m/min时,电流峰值持续时间增加了1倍左右,同时电弧宽度与电流密度的随之增加,使得熔滴过渡过程中电磁力上升,熔滴尺寸下降14%且射滴过渡频率增加了3~4倍。当瞬时电流进入熄弧阶段时,熔滴过渡形式转变为短路过渡。随着送丝速度的增加,短路过渡频率从29 Hz减少至20 Hz。 相似文献
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超声辅助MIG焊接中超声作用特性研究 总被引:2,自引:0,他引:2
超声辅助熔化极惰性气体保护(Ultrasonic assisted metal inert gas,U-MIG)焊是一种新型熔化极焊接方法,利用外加声场将相应声学效果引入焊接熔池达到改善接头性能的目的。通过试验系统化研究超声对电弧形态、熔滴过渡以及接头宏观形貌的作用规律,主要目标是更好地理解超声在不同焊接条件下的作用特点。对高速摄像采集的电弧数据进行处理,结果发现随电弧电压增加,超声对电弧的压缩效果也逐渐增大;而随送丝速度增加,焊接电流增大,电弧压缩效果减弱。针对熔滴受力特点分析,可以看出超声作用后熔滴会受到一个促进熔滴过渡的附加力作用。在焊接电流为200 A时,该附加力达到最大,约为2.8×10-3 N,继续增大焊接电流,该附加力逐渐降低。对比不同送丝速度时焊缝宏观形貌,结果显示为了获得更高的焊接效率不能无限提高送丝速度,存在一个最佳的参数匹配值。结合平面驻波理论分析,随温度增加,声辐射力逐渐减弱,这在一定程度上也会削弱附加力作用效果。利用熔池薄膜模型探讨电弧、熔滴过渡以及熔池振荡三者之间的关系,超声对电弧形态、熔滴过渡的影响均可改变熔池的振荡特性,这间接表现为接头形貌的改变。通过试验与理论分析,为U-MIG焊接方法进一步发展与应用打下坚实基础。 相似文献
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Wang Zhang Xueming Hua Wei Liao Fang Li Min Wang 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):935-942
The plasma behavior and metal transfer in CO2 laser?+?GMAW-P hybrid welding have been investigated. A 650 nm laser, in conjunction with the shadow graph technique, is used to observe the metal transfer process. The effect of the mutual distance and laser power on the metal transfer has been discussed. The results indicate that the laser-induced plasma plume have a significant impact to the arc shape, resistance, electrode melting, droplet formation, detachment, and impingement onto the workpiece. The laser-induced plasma changes the conductive path and forces affecting on the droplet. High laser power and short distance between laser beam and arc (DLA) reduce the pulse base time (PB) of the voltage of phase, increase the droplet detachment time (PD) and the pulse current time (PP) of the voltage of phase, and it also lead to an upward and inward force near the bottom of the droplet. As a consequence, the droplet formation time is increased, and eventually an off-axis droplet phenomenon is deduced. The vapor jet force induced by the the keyhole plasma acts on the droplet as a retention force; this force decreases when the DLA becomes larger and increases when the laser power becomes higher. The observation may help in understanding the weld characteristics with respect to variation in mutual distance and laser power which may be beneficial in using the main process parameters to produce desired weld quality. 相似文献
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研究激光和Ar+He混合气体中He气体体积分数对激光+双丝脉冲MAG复合焊焊接稳定性的影响。搭建激光+双丝脉冲熔化极活性气体保护(Metal active-gas, MAG)复合焊焊接系统,利用LabVIEW信号采集系统采集焊接电流和电弧电压波形,借助高速摄像系统同步拍摄电弧形态和熔滴过渡过程,实时监测焊接过程。观察后丝短路和前丝断弧情况并对前丝电弧电压进行单因素方差分析,研究Ar+He混合气体中He气体体积分数对焊接稳定性影响;比较焊接过程中激光的有无对熔滴过渡的影响,分析激光对焊接稳定性影响。结果发现随着He气体体积分数增大,后丝对应短路次数增多,当He气体体积分数为50%时,前丝出现断弧现象,大于50%,断弧时间随之增加,焊接稳定性变差;激光+双丝脉冲MAG复合焊和双丝脉冲MAG复合焊相比,加入激光可稳定电弧,为熔滴提供一附加力,该力促进熔滴过渡,使熔滴过渡尺寸减小,加大过渡频率,改善熔滴过渡,提高焊接稳定性。 相似文献
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脉冲MIG焊建模仿真分析及弧长控制 总被引:1,自引:0,他引:1
针对脉冲MIG焊过程中的电弧稳定性问题,建立基于尖端不稳定熔滴过渡理论的焊丝熔化动态电弧模型,并对焊接过程中的电弧电压、电弧长度及熔滴过渡尺寸进行仿真,得到与实际焊接相似的电弧电压波形,分析脉冲电流下熔滴过渡频率及影响电弧稳定性的因素,且进行弧长稳定控制的仿真研究,在此基础上运用快速原型技术建立铝合金脉冲MIG焊控制系统,采用电弧电压反馈对铝合金脉冲MIG焊过程进行送丝调节的弧长控制试验。研究表明:所建立的铝合金脉冲MIG焊焊丝熔化动态电弧模型很好反映了实际焊接过程,揭示出脉冲MIG焊焊接过程中熔滴过渡时间间隔具有一定的不确定性和电弧长度的不稳定性,通过电弧电压反馈控制可显著改善铝合金脉冲MIG焊过程电弧系统的稳定性。 相似文献
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Yun Long Chang Xiao Long Liu Lin Lu A. S. Babkin Bo Young Lee Feng Gao 《The International Journal of Advanced Manufacturing Technology》2014,70(9-12):1543-1553
In gas metal arc welding, electromagnetic force, plasma stream force, gravity, and surface tension are the most important factors that affect metal transfer and spatter generation rate. In this paper, different kinds of external electromagnetic fields were introduced to gas metal arc welding (GMAW). The photos of arc plasma and droplet and electric signals covering welding current and arc voltage were acquired synchronously by an analysis and evaluation system based on LabView for GMAW. It was confirmed that the metal transfer frequency was improved, and spatter generation rate was diminished under controls of external electromagnetic fields. The influencing rules of external electromagnetic fields on electromagnetic force, the gravity, the plasma stream force, and surface tension were studied by three physical models, and the mechanism of external electromagnetic fields was revealed. This paper is for the purpose of discussing these factors and will make a profit for the application of electromagnetic coupling control to short-circuit GMAW. 相似文献
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CHARACTERISTICS OF DROPLET TRANSFER IN CO2 LASER-MIG HYBRID WELDING WITH SHORT-CIRCUITING MODE 总被引:1,自引:0,他引:1
LEI Zhenglong CHEN Yanbin LI Liqun WU Lin State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin China 《机械工程学报(英文版)》2006,19(2):172-175
LF6 aluminum alloy plates with 4.5 mm thickness are welded in this experiment.Welding is carried out by using the CO2 laser-MIG paraxial hybrid welding in flat position. The experimental results indicate that the inherent droplet transfer cycle time of conventional MIG arc is changed due to the interaction between CO2 laser beam and MIG arc in the short-circuiting mode of laser-MIG hybrid welding. Because of the preheating action of CO2 laser to electrode and base material, the droplet transfer frequency of MIG arc is increased in the hybrid welding process. When laser power is increased to a certain degree, the droplet transfer frequency is decreased due to the effect of laser-induced keyhole. Furthermore, through analyzing the MIG welding current and arc voltage waveforms and the characteristics of droplet transfer in the hybrid welding process, the effect of laser energy and the action point between laser beam and arc on the frequency of droplet transfer and weld appearance is investigated in details. 相似文献
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Xueping Ding Huan Li Lijun Yang Ying Gao 《The International Journal of Advanced Manufacturing Technology》2013,69(1-4):107-112
A numerical model based on fluid dynamics theory and electromagnetic theory is developed to simulate the dynamic metal transfer process in tandem gas metal arc welding (T-GMAW). The relationship between welding current and surface tension coefficient is modified by analysis of regression in this model. The numerical simulation of the metal transfer process in T-GMAW is compared with that in single-wire gas metal arc welding (SW-GMAW). It is found that a droplet transfers axially in SW-GMAW, but the droplets transfer non-axially in T-GMAW. To verify the accuracy of simulated results, the welding experiments were performed in which the actual metal transfer processes were recorded by high-speed photography. The simulated results are in good agreement with the experimental ones. This transfer behavior in T-GMAW is analyzed by studying the distributions of physical quantities including pressure, velocity, and electric potential of the droplet. The simulated results reveal that the electromagnetic force between two droplets results in the different metal transfer process. With the increase of the welding current, the surface tension coefficient decreases and the electromagnetic force increases. As a consequence, the metal transfer process in T-GMAW is accelerated. 相似文献
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针对CO2短路过渡气体保护焊过程中的飞溅问题,通过焊接质量分析仪采集电压、电流动态信息,找到与飞溅相关的熔滴缩颈、熔滴短路和熔滴小桥爆断时刻的标志信息,为短路过渡气保焊过程在线监控提供高品质的信息源。 相似文献