共查询到20条相似文献,搜索用时 184 毫秒
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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. 相似文献
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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. 相似文献
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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。 相似文献
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埋弧焊电弧超声激励及其热动力学效应 总被引:2,自引:0,他引:2
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。 相似文献
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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. 相似文献
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《Science & Technology of Welding & Joining》2013,18(3):186-191
AbstractUltrasonic 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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Jianfeng Wang Jinping Liu Bin Wang Jicai Feng 《Science & Technology of Welding & Joining》2017,22(6):465-471
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. 相似文献