逆变弧焊机电弧推力自适应控制系统

在焊接电流确定的条件下,引弧瞬间的焊机输出电压反映了焊接电缆长度、截面积以及连接情况等重要信息。本研究装置是基于MC68HC11单片机控制的逆变焊机电弧推力自适应的控制系统,首先通过对引弧瞬间焊机输出电压的实时检测,实现了电弧推力拐点电压随焊接电流及焊接电缆长度,截面积等改变而自动;然后通过对焊接电弧 实时检测与模糊处理控制焊机的输出电流,从而使MMA手工电弧焊的以推力控制具有很强的自适应能力。     

Stability of pulsed-arc consumable electrode welding

Experiments were carried out to determine the conditions of the stability of the processes of pulsed-arc consumable electrode welding without short-circuiting the arcing gap for rectangular pulses. The experimentally determined conditions of the relative constancy of average or effective current are used to determine the conditions for the stability of the processes of pulsed-arc consumable electrode welding for rectangular pulses in welding in argon and argon-containing mixtures.     

Arc behavior in two wire tandem submerged arc welding

The behavior of leading and trailing arc root dimensions and arc interaction in the two-wire tandem submerged arc welding process was studied using real-time recorded current and voltage waveforms, and CCD arc images for a wide range of experimental conditions. Physical and regression equations were developed to predict the arc interaction and dimensions as a function of the welding condition. The influence of the arc interaction on the molten droplet transfer direction was studied. The arc center displacements (arc interaction) under different welding conditions were fairly well predicted by the corresponding physical models. The arc root dimensions were unsymmetrical and increased with an increase in the welding current and voltage while the same decreased with the increase in the arc center displacements. This variation was reasonably envisaged by the developed regression models. The detached molten electrode droplet followed the arc axis at the time of detachment and deposited into the weld pool.     

加电弧推力的多功能逆变焊机

通过控制电路的巧妙设计改变弧焊电源外特性（即静特性），给出了多功能焊机手工焊接时加电弧推力的一种方法及其电路原理。     

Arc behaviour and weld formation in gas focusing plasma arc welding

ABSTRACT

Improving penetrability is a key issue in plasma arc welding (PAW). Increasing plasma energy is one way to improve arc penetrability. Gas focusing plasma arc welding (GF-PAW) platform is self-designed and developed. Role and action mechanism of focusing gas is initially studied. Focusing gas makes no obvious effects on arc pressure distribution and value. Focusing gas changes arc temperature distribution outer orifice, while focusing gas does not affect arc temperature distribution inner orifice. Focusing gas can constrict arc and arc energy increases 210?W with an increase in arc voltage of 1.4?V. GF-PAW can fully penetrate the whole work-piece while PAW can only partially penetrate the work-piece under welding current 150?A. GF-PAW can improve penetrability, and may increase welding speed, and has a potential application in manufacturing.     

Metal transfer and arc behaviour of novel consumable and non-consumable electrode indirect arc droplet welding

Abstract

The consumable and non-consumable electrode indirect arc droplet welding is a novel method that applies an indirect arc generated between a consumable electrode and a non-consumable electrode to welding. It was successfully used to overlap join the thin zinc coated steel plate. In the point to point (consumable electrode and non-consumable electrode) configuration, the stable metal transfer was obtained. The globular, projected spray and streaming spray transfer modes were promoted. With the increase in welding power, the metal transfer became faster and more stable. At the same time, the indirect arc became brighter, smaller and more stable. The arc self-regulation guaranteed the stable burning of the indirect arc. The desire stability was observed from the fluctuation of the welding current and the arc voltage waveforms. The side concentrated melting on the root of the droplet produced high pinch effect, which facilitated the detachment of the droplet.     

焊接电弧的等离子流力

以试验为基础，分析了直流ＴＩＧ电弧阳极热斑表面等离子流力的径向分布，数学表达式，电弧长度及电流的影响，阐述了该力在整个电弧机械作用力中的地位。     

铸铁冷焊的弧焊电源的研制

介绍了将ZX5-250弧焊电源改制为脉冲电源进行铸铁冷焊的方法。经实验试焊证明，改制后的电源能完全满足铸铁冷焊的要求。     

洛伦兹力计算及其对GMAW焊接模拟的影响

运用两种方法给出洛伦兹力求解的完备公式，并通过数值仿真验证.详细推导了洛伦兹力的两种求解过程，采用ANSYS软件分别对熔滴过渡和电弧作了数值模拟，对洛伦兹力分布图、熔滴过渡和电弧形态作了详细比较，分析动量源项对焊接仿真结果的影响.结果表明，与直接进行积分求解的近似方法相比，引入磁矢量的间接计算法对焊接数值模拟效果较好，洛伦兹力分布更接近于理论分析；未添加洛伦兹力源项的计算电弧没有被有效的压缩，熔滴也没有缩颈；间接法有更广的适用范围.     

变极性TIG焊电弧压力分析

采用压力传感器获取不同条件下的变极性钨极氩弧焊(VPTIG)横焊时的电弧压力,研究分析了电弧压力在径向上的分布规律,对比研究了直流TIG焊、反极性期间占5%,15%的变极性TIG中心电弧压力.结果表明,变极性TIG焊电弧压力的径向分布属于双面指数分布.焊接电流在100~140 A范围内,在电流均值相等的情况下,由于反极性期间电子发射机制和电弧发散等原因,随着一个周期内钨极为正半波的时间比例增加,电弧压力逐渐减小,且焊接电弧积分力与电流的平方近似成正比例关系.     

Integrated model for assessment of electromagnetic force field due to arc welding

Abstract

Computation of the electromagnetic force over a wide range of consumable arc welding parameters is difficult with available models because of the need for experimentally evaluated electrode extension for every individual set of parameters. This becomes more complicated in case of submerged are welding, because the welding arc remains buried beneath flux. This study presents a new approach of integrating mechanistic model of electrode extension with the computational model of electromagnetic force, wherein the apparent electrode extension is obtained by solving the electrode melting rate equation. The proposed approach is demonstrated through a case on submerged arc welding. The effect of current, voltage, electrode diameter, contact tip to workpiece distance and polarity, on the electromagnetic force, is determined and analysed. This investigation shows that detrimental effects of welding electromagnetic force can be restricted without compromising productivity because after initial rapid increase, no considerable change in melting rate is caused by the force under consideration.     

高压环境下电弧电特性及管道焊接工艺的研究

利用自制的高压干法水下焊接模拟试验平台,首次研究了高压空气环境下的GTAW电弧电特性,研究表明:随着环境压力的升高,气体密度增大,电离度降低,弧柱电场强度增加,导致电弧静特性曲线上移.利用多元线性回归方法,建立了高压空气环境下的电弧电压教学模型,并在此基础上进行了高压模拟管道焊接工艺试验.研究表明,随着环境压力的增大,焊接电流减小,Ar流量增大.在0.1,0.3,0.5和0.7 MPa压力下,选用合理的焊接工艺参数,对于X56管线钢,均获得单面焊双面成形的良好效果.     

Arc characteristics of twin-wire indirect arc gas shielded welding

Twin-wire indirect arc gas shielded welding is a novel welding method. By recording the arc shape and welding parameters, the effects of welding parameters and included angle on arc characteristics are discussed in this paper. The experimental results show increasing welding current can prompt centralized and straight of arc due to increasing plasma force and electric magnetic pinch effect. Increasing arc voltage can increase the size and brightness of the arc, as a result of increasing arc energy. The reducing of included angle increases the electric magnetic pinch effect, the arc becomes slender and supplies higher energy. It is thought the smaller included angle is beneficial to obtain perfect weld bead.     

Effect of exothermic additions on heat generation and Arc process efficiency in Flux-Cored Arc welding

The focus of this research was to determine the effectiveness of exothermically reacting chemical additions to the flux in the Flux-Cored Arc (FCA) welding process. The heat delivery and weldbead morphologies of exothermically assisted FCA welding were experimentally studied with a self-shielded FCA flux formulation. The exothermic additions consisted of stoichiometric mixtures of aluminum, magnesium and aluminum/magnesium (50/50 wt.%) flux with the mineral hematite systematically displacing iron powder. Exothermic flux additions to FCA welding can assist in the generation of heat and improve arc efficiency. The Al/Mg (50/50) electrodes were significantly more effective than aluminium or magnesium flux additions in composite gain value. The weldment dilution increased with exothermic addition. However, overall dilution with exothermic addition was not higher than baseline value except with a 10 wt.% magnesium addition. Weld deposition was most enhanced by Al/Mg (50/50) additions, showing a greater electrode melting efficiency and a larger weldbead than with magnesium-rich and aluminum-rich additions, respectively.     

带状电极MAG焊电弧行为

用高速摄像系统和电流电压采集模块对带状电极MAG焊工艺电弧行为进行了研究.结果表明,带状电极MAG焊电弧呈非柱对称分布,电弧截面从钢带端部到母材逐渐由椭圆形过渡到圆形.随焊接工艺参数的增大,电弧能量提高,钢带端部由多个电弧共存转变为一个电弧燃烧,电弧沿钢带无规律的紊乱运动转变为较稳定的左右摆动,进而转变为不发生明显摆动...     

脉冲埋弧横焊工艺在石油储罐焊接中的应用

把横焊位置脉冲埋弧焊的熔池简化为在固体表面承受脉冲载荷的液态金属,分析了其横焊位置的受力情况,探索了脉冲埋弧横焊消除咬边的机理,熔池所受到的电磁力、熔滴冲击力以及表面张力都是随焊接电流的变化做周期性变化,这样的周期性变化有利于在填充焊和盖面焊中消除咬边.结果表明,脉冲埋弧横焊不仅可以利用脉冲峰值电流保证熔深,同时脉冲电流的震荡作用可以有效地消除咬边,拓宽了埋弧横焊的工艺参数范围.     

Nd:YAG激光+CMT复合热源电弧形态和熔池形貌

以304不锈钢为研究对象,借助高速摄像记录了YAG激光+CMT复合热源焊接的电弧形态和熔池形貌,研究了不同激光功率和光丝间距下的YAG激光+CMT复合热源焊接的电弧形态和熔池彤貌,并与CMT焊接进行了比较,分析了YAG激光+CMT复合热源焊接的电弧形态和熔池形貌发生变化的机理.结果表明,在Nd:YAG激光+CMT复合热...     

高效弧焊技术研究现状

近年来高效焊接技术受到了制造行业的广泛重视,在保证焊接质量前提下,提高焊接效率以满足现代制造业发展的需求是未来发展趋势之一,因此开展弧焊技术的研究具有十分重要的理论意义和工程实用价值。对国内外弧焊方法的研究发展现状进行了介绍和总结,包括带极GMAW、T. I. M. E.、双丝及多丝焊、高速脉冲GMAW、A-TIG、热丝TIG及复合热源焊等高效弧焊技术的原理及研究现状进行总结,并对其焊接特点及发展趋势进行了详细阐述。     

水下湿法药芯焊丝焊接电弧稳定性

利用焊接电弧电压信号的标准差和差异系数的倒数作为评价电弧稳定性的指标,通过试验研究了不同工艺条件下水下湿法药芯焊丝焊接的电弧稳定性．建立了湿法焊接电弧稳定性的敏感度模型,分析了各工艺参数如焊接电流、电弧电压、焊接速度和水深对湿法药芯焊丝焊接电弧稳定性的影响．结果表明,水深增大时,焊接电弧稳定性变差,特别是在浅水区域,增大水深可显著降低电弧稳定性;焊接速度增大,电弧稳定性变差;焊接电压对电弧稳定性影响很大,适当提高焊接电压可提高电弧的稳定性．     

外加纵向磁场作用下的TIG焊接电弧

以单粒子理论假设为基础,详细阐述了外加纵向磁场在等离子体中的不均匀分布形态,以及这种不均匀磁场对TIG焊接电弧形状的影响,分析了电弧区的受力情况,建立了等离子体中带电粒子在这种非均匀磁场中的运动方程.由分析可知带电粒子在磁场作用下的运动轨迹是一条汇聚的螺旋线,且等离子弧外围的带电粒子的圆周运动的速度远大于弧柱中心的粒子运动速度.结果表明,在外加纵向磁场的作用下,TIG焊电弧发生了明显的收缩,激磁电流一定,激磁频率越高,电弧收缩越明显.