电弧超声对Q235A的SMAW焊缝组织和性能的影响

作为焊接电弧的热源，对其施加高频调制后可变成可控的超声发射源。通过对比常规SMAW和电弧超声作用下SMAW的Q235A焊缝组织，发现电弧超声能够细化熔合区晶粒，并使得粗晶区宽度变窄；同时．磁记忆检测法的结果表明，电弧超声改善了焊接接头的残余应力分布。     

电弧超声对Q235A的SMAW焊缝组织和性能的影响

作为焊接电弧的热源,对其施加高频调制后可变成可控的超声发射源。通过对比常规SMAW和电弧超声作用下SMAW的Q235A焊缝组织,发现电弧超声能够细化熔合区晶粒,并使得粗晶区宽度变窄;同时,磁记忆检测法的结果表明,电弧超声改善了焊接接头的残余应力分布。     

电弧超声埋弧焊改善09MnNiDR焊缝组织性能

作为焊接电弧的热源,对其施加高频调制后可变成可控的超声发射源。通过对比常规SAW和电弧超声作用下SAW的09MnNiDR焊缝组织,发现电弧超声能够减小埋弧焊焊缝区的柱状晶尺寸和先共析铁素体的晶粒大小,同时低温冲击实验结果表明,电弧超声能够显著提高09MnNiDR焊缝区的冲击吸收功。     

电弧超声埋弧焊改善09MnNiDR焊缝组织性能

作为焊接电弧的热源。对其施加高频调制后可变成可控的超声发射源。通过对比常规SAW和电弧超声作用下SAW的09MnNiDR焊缝组织。发现电弧超声能够减小埋弧焊焊缝区的柱状晶尺寸和先共析铁索体的晶粒大小，同时低温冲击实验结果表明，电弧超声能够显著提高09MnNiDR焊缝区的冲击吸收功。     

超快变换高频变极性方波TIG电弧行为

基于一种新型电路变换拓扑实现频率达超音频段且具有超快速电流上升沿和下降沿变化速率的高频变极性方波电流输出,将其用于铝合金TIG焊接过程,研究分析高频变极性TIG电弧行为.结果表明,变极性电流频率和变化速率具有对电弧形态、稳定性及电弧力的控制能力,提高电流极性变换频率,电弧清除氧化膜的能力增强,电弧表现出明显的收缩效应,电弧电压和电弧等效电阻增大,但电弧偏吹作用加剧.在一定频率范围内,增加变极性电流频率,减小负极性电流幅值及其持续时间,可增大焊缝熔透率,有利于提高焊接效率和质量.     

影响电弧超声激发强度的参数

为了加深对电弧超声激发的认识,更好的控制电弧超声,研究了影响电弧超声激发强度的参数.首先搭建了一套电弧超声焊接系统信号检测平台,用以记录电弧超声焊接过程中电信号与声信号.结果表明,该系统能够有效的记录试验过程中的信号变化.在此基础上设计试验,测定不同参数条件下,空气中和试板上的电弧超声信号的强度变化趋势,最终得出激励能量是影响电弧超声激发强度的主要因素,并建立了激励能量与激发电弧超声强度间的关系,这为研究电弧超声改善焊接接头组织和性能的作用机制提供了试验数据.     

受激电弧超声发射实验研究

为开发可控的电弧功率超声,选取熔化极和非熔化极气体保护电弧作为受激对象,设计了电弧以超声激励激,在电弧回路中分别施加高频连续交变信号和敲击式脉冲信号,成功地激发电弧超声发射,实现了使电弧集“产热与声发射”功能于一体的新型控制机理。根据电弧声发射波形分析了受激电弧对激励信号的线性和非线性频率响应特点,为进一步探索频率,幅度等参数实时可控的功能超声柔性控制方法奠定了基础。     

电弧超声提高电弧喷涂铬涂层的结合强度

提出了用电弧超声方法提高电弧喷涂铬涂层结合强度的新方法.作为电弧喷涂的热源,在对其施加高频调制之后,喷涂电弧可以作为超声发射源.电弧超声改善了喷涂材料的雾化效果,提高了涂层的结合强度,而且结合强度随着超声频率和激励电压的提高而提高.     

埋弧焊电弧超声激励及其热动力学效应

为研究电弧超声激励的一般规律和电弧超声的热力学与动力学效应，选择超声频段的高频激励源与常规工频埋弧焊电源进行电磁耦合，在燃弧过程中激励出电弧超声，并对声发射信号进行了频谱分析。采用大弧焊参数并分别施加不同的激励频率进行埋弧焊试验，对焊接试样的熔合区与热影响区形态进行观察，研究熔合区和热影响区在电弧超声影响下的形态变化规律，并据此对电弧超声的热力学和动力学效应进行了初步探讨。     

利用电弧超声改善电弧喷涂质量的研究

提出用电弧超声方法作为改善喷涂涂层质量的新方法。作为电弧喷涂的热源，在对其施加高频调制之后，喷涂电弧可以作为超声波的发射源而作用于喷嘴内的雾化微粒。超声波的空化效应，机械效应和热效应加强了喷涂材料的雾化效果。从能量的角度研究了电弧超声的应用使得喷涂粒子的粒度变小，飞行速度加快，提高了喷涂的生产效率，制备出的涂层强度提高，孔隙率降低的机理。     

新型逆变CO2焊机的控制原理与特点

依据CO2焊接工艺的特点，设计了一种电子电抗器控制的逆变弧焊电源。当短路发生后，电流先保持在一较低值，然后以斜率可以调节的双折线规律上升。在燃弧阶段，调节控制回路参数，控制燃弧电流的变化速度，保证充足的燃弧能量。设计了专门的引弧和收弧电路。试验表明，该焊机具有飞溅小，成形好，去球效果好，容易引弧等优点。     

弧焊逆变电源动态性能的提高及其对短路过渡焊接过程的影响

采用可饱和输出电感大幅度提高了弧焊逆变电源的动态性能。在此基础上,研究了电源动态特性对ＣＯ２短路过渡焊接过程的影响规律。研究结果表明,增大短路后期电流的下降速度可以有效地减小焊接飞溅,而提高短路中期电流上升速度则有利于短路过渡焊接过程的规则性与稳定性。     

脉冲电流参数对奥氏体不锈钢电弧行为的影响

基于0Crl8Ni9Ti奥氏体不锈钢超高频脉冲钨极氩弧焊（UHF—GTAW,ultrahigh frequency pulse gastungsten arc welding）试验,分析了脉冲电流参数对奥氏体不锈钢电弧行为的影响及其作用规律．结果表明,以脉冲电流频率、占空比为代表的脉冲电流参数对不锈钢UHF-GTAW电弧的电学特性、工作形态、电弧力及熔透特性具有较大影响,随着超高频脉冲方波电流频率的增加,电弧收缩效应增强,电弧覆盖面积在一定范围内减小,电弧力显著增长,以等离子流力及电磁力为主的轴向力作用于熔池表面液态金属,造成熔池表面凹陷、热源下移、焊缝熔深增大、熔透率显著提升．     

Research on short circuiting transfer mode of ultrasonic assisted GMAW method

Abstract

Ultrasonic assisted gas metal arc welding (U-GMAW) has been recently developed to improve the metal transfer characteristics. The ultrasonic wave is applied on the metal transfer process by means of an acoustic field. Welding electrical signal measurement and high speed camera are employed to study the differences of short circuiting metal transfer between conventional GMAW and U-GMAW. Compared with the conventional GMAW, the short circuit frequencies of U-GMAW are obviously increased under the same welding parameters. Moreover, the voltage range of the stable short circuiting transfer is enlarged, and the weld appearances become more uniform with the action of the ultrasonic wave. The high speed video images indicate that the U-GMAW arc is compressed and the electrical field intensity is increased. The decrease in the arc length is the main reason for the increase in the short circuit frequency.     

Influences of acoustic field parameters on welding arc behavior in ultrasonic-MIG welding

By applying ultrasonic-MIG welding as research object, the behaviors of welding arc were analyzed with varied ultrasonic parameters in welding using arc images recorded by high-speed camera. The influences of the current by exciting ultrasonic and the height and shape of ultrasonic radiator on welding arc were studied. Results showed that when the current was 150 mA, ultrasonic showed most distinct compressive effect on arc. The compressive volumes of arc length at different heights were calculated by adjusting the height of ultrasonic radiator continuously from 10 mm to 35 mm, there were three maximum points. The compressive degrees of them reduced successively. By utilizing different shapes of ultrasonic radiator, it revealed that ultrasonic radiator with spherical crown surface showed better compressive effect in a larger welding standard scope. When radius of radiator increased, axial compressive volume of arc enlarged, while an increasing curvature radius led to more distinct radial compression of arc.     

Improving weld quality of 09MnNiDR steel by using arc-excited ultrasonic

An experimental setup to excite ultrasonic by modulating electrical arc was applied in the submerged arc welding （SAW） process of 09 MnNiDR steel to study its effect on quality of the welds. Arc-excited ultrasonic energy refines grains of the welds and more acicular ferrite （ AF） appears in the fusion zone. It also enhances impact toughness of the joints at -70 ℃ significantly. With the ultrasonic of 50 kHz, the toughness is improved by 47% in the fusion zone and by 82% in the heataffected zone （HAZ）. The fractography of welds shows that the fracture is changed from cleavage fracture to gliding fracture while applying ultrasonic vibration.     

水深环境下湿法焊接声压替代图像信号可行性分析

水深环境下水下湿法药芯焊丝焊接(FCAW)受周围电弧气泡生长的影响,其状态需要通过信号采集. 文中首先搭建水下湿法焊接试验平台,进行湿法药芯焊丝焊接试验,对焊接过程中的气泡声压信号、高速摄像信号、电弧电流电压信号,进行同步采集;然后对比了引弧阶段下浅水和20 m水深的气泡动态演变图像及其声压信号,结合20 m水深稳弧阶段信号,发现气泡脉冲声信号与气泡图像在气泡大小、爆破周期等演变细节上有着很好的对应关系,但随着水深增加,烟尘导致图像信号更加模糊. 最后对水下20,40 m的环境中获取到的电弧从引弧到稳弧阶段的声电信号,进行对照分析. 结果表明,气泡声压信号可以清晰地反映出气泡的变化状态,深水下声压信号替代高速摄像具有可行性.     

水下湿法药芯焊丝焊接气泡动态演变与其声脉冲分析

水下湿法药芯焊丝焊接(FCAW)以操作适用性好等优点在海洋设施维修中占有重要地位,焊接区域周围动态变化的气泡生长会影响焊接电弧的稳定性. 文中通过搭建水下湿法焊接试验平台,进行了湿法药芯焊丝焊接试验,利用传感器对焊接过程中的电弧电流电压信号,气泡声信号以及气泡高速图像进行了同步采集;研究了气泡声信号与气泡高速图像的对照关系,并对气泡声信号与电弧电流电压信号进行同步分析,获得了不同电弧燃烧状态下的气泡演变行为,以气泡声信号的变化来反映气泡演变对水下湿法焊接电弧燃烧的稳定状态的影响. 结果表明,气泡声信号可以清晰地反映焊接电弧燃烧的各种状态,能对不同气泡演变模式进行分类,并可从中分析其与电弧燃烧特性的对应关系.     

Effect of pulsed ultrasonic on arc acoustic binding in pulsed ultrasonic wave-assisted pulsed gas tungsten arc welding

This paper investigated the effect of pulsed ultrasonic on the microstructure and mechanical properties of weld joints using novel pulsed ultrasonic wave-assisted pulsed gas tungsten arc welding. The principle of proposed method was to apply pulsed ultrasonic to the welding process during background current. The results indicated that arc contraction degree, weld pool oscillation, and weld penetration were remarkably enhanced by applying pulsed ultrasonic. The microstructure refined by pulsed ultrasonic was much finer than those refined by continuous ultrasonic due to the more stable ultrasonic field in arc zone and consequent stronger fluid flow in weld pool. Furthermore, tensile strength of the joints with pulsed ultrasonic was significantly improved compared with that of the joints with no and continuous ultrasonic.     

基于亚像素的埋弧焊焊缝图像处理

埋弧焊是普遍使用的熔焊方法之一,具有生产效率高、焊缝成形好、没有弧光辐射等诸多优点,应用前景广阔.为了提高埋弧焊焊接过程的自动化和智能化,对埋弧焊精密跟踪技术的要求不断提高,需对焊缝间隙和坡口边缘进行精密检测.在此提出了一种基于B样条变换的亚像素定位算法,该算法是在对图像进行一次Marr-Hildreth边缘检测后再进...