scholarly journals Study on Time Characteristics of Coupling Discharge in Pulsed Laser Induced Double-TIG Welding

2021 ◽  
Author(s):  
Xinkun Xu ◽  
Huanyu Yang ◽  
Liming Liu
Keyword(s):  
High Speed ◽  
Pulsed Laser ◽  
Pulse Action ◽  
Tig Welding ◽  
Duty Ratio ◽  
Regulation Mechanism ◽  
Arc Plasma ◽  
Existence Time ◽  
Arc Pressure ◽  
Marangoni Force

Abstract Based on the dynamic behavior of laser keyhole, the time characteristics of coupling discharge of heat source in pulsed laser induced double-TIG welding (LIDTW) are studied. The behaviors of arc plasma and laser keyhole were directly observed by high-speed camera and auxiliary illumination source. The physical characteristics of arc plasma were analyzed by spectrometer and arc quality analyzer. A physical model is established to reveal the regulation mechanism of time characteristics of coupling discharge. It is found that after laser pulse action the coupling discharge between keyhole plasma and double-arc plasma does not end immediately, and its time depends on the existence time of keyhole. During hybrid welding, when the combined force of arc pressure and Marangoni force can overcome the gravity, the liquid metal is forced out of the keyhole and the keyhole remains open. Improving the electron density of arc plasma and arc voltage and reducing the diameter of arc conductive channel by selecting appropriate parameters to is the key to prolong the existence time of keyhole, which is beneficial to improve the welding penetration. The coupling enhancement of double-arc electromagnetic field in LIDTW can effectively suppress keyhole backfill and increase the duty ratio of coupling discharge. When the total current intensity is 200 A, compared with laser induced single-TIG welding (LISTW), the existence time of keyhole in LIDTW increases by 77 %, the duty ratio of coupling discharge increases by 12 %, and the weld penetration increases by 29.2 %.

scholarly journals Effect of Laser on Double-Arc Physical Characteristics in Pulsed Laser Induced Double-TIG Welding

2021 ◽  
Author(s):  
Liming Liu ◽  
Xinkun Xu ◽  
Guomin Xu ◽  
Zhaodong Zhang
Keyword(s):  
Heat Source ◽  
High Speed ◽  
Pulsed Laser ◽  
Physical Characteristics ◽  
Particle Migration ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Horizontal Distance ◽  
Arc Plasma ◽  
Total Electron

Abstract In order to improve the energy utilization efficiency of double-TIG arc, based on the synchronous induction of pulsed laser to double-arc, the coupling-enhanced discharge phenomenon between double-arc is studied in this paper. The energy utilization efficiency of pulsed laser induced double-arc is quantitatively analyzed. The physical characteristics of coupling double-arc are studied based on high-speed camera and spectral diagnosis technology. The physical model is established to discuss the particle migration during the coupling discharge, characterizing the movement state of electrons. The results show that Dla (horizontal distance between the tungsten electrode tip and laser beam axis) has a significant effect on the energy utilization efficiency of the heat source. With the increase of Dla, there are three interaction relationships between the double-arc plasma and keyhole plasma: Mutual interference, Coupling-enhanced discharge and No interaction. A suitable Dla can realize the synchronous induction of laser to double-arc plasma, forming a coupling double-arc, the heat source has a higher energy utilization efficiency. The migration of particles in double-arc can be divided into four stages: Double-arc free discharge stage, Laser-induced initial stage, Laser-induced contraction stage and Laser-induced stable stage. Under the induction of laser, the double-arc forms a common compressed conductive channel. The energy density of coupling double-arc reaches 9.3 times that of traditional double-arc, and the total electron kinetic energy increases by 38% compared with traditional double-arc.

scholarly journals Influence of Cusp External Magnetic Field on Deposition Rate of Two-electrode TIG Welding

2021 ◽  
Author(s):  
Liming Liu ◽  
Yanli Zhu ◽  
Runtao Liu
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Deposition Rate ◽  
Welding Current ◽  
Tig Welding ◽  
Arc Plasma ◽  
Arc Voltage ◽  
Arc Pressure ◽  
Arc Shape ◽  
Two Parameters

Abstract Experiments have been conducted to investigate the influence of the cusp external magnetic field (EMF) on deposition rate of two-electrode tungsten insert gas (T-TIG) welding. T-TIG arc parameters such as arc shape, arc voltage, arc pressure and arc plasma information were acquired respectively. Results showed compared to TIG, a higher welding current could be allowed for T-TIG, due to its low arc pressure characteristic. Under the effect of the cusp EMF, the arc shape was compressed along x-axis of T-TIG, while elongated along y-axis of T-TIG. Besides, the peak arc pressure of T-TIG was not significantly increased by the cusp EMF. Moreover, with the action of the cusp EMF, the maximum values of the electron temperature (Te) and electron density (Ne) of T-TIG were not significantly increased, but along y-axis, the increments of the two parameters were gradually increased and their distributions were widened. Therefore, more arc energy was allocated on y-axis of T-TIG by the cusp EMF, which could improve the preheating and the melting of the filler wire along y-axis, so the deposition rate of T-TIG could be increased by 17.6% under the effect of the cusp EMF.

Study on Fast-Convert Ultrasonic Frequency Pulse TIG Welding Arc Characteristic

2011 ◽  
Vol 704-705 ◽  
pp. 745-751 ◽  
Author(s):  
Bo Jin Qi ◽  
Ming Xuan Yang ◽  
Bao Qiang Cong ◽  
Wei Li
Keyword(s):  
Pulse Current ◽  
Current Level ◽  
Tig Welding ◽  
Ultrasonic Frequency ◽  
Arc Plasma ◽  
Arc Voltage ◽  
Welding Arc ◽  
Huge Impact ◽  
Pulse Peak ◽  
Frequency Pulse

Based on ultrasonic frequency pulse tungsten inert-gas (TIG) welding for 0Cr18Ni9Ti austenitic stainless steel, the influence of pulse level parameters was investigated on the field of arc characteristic and arc force. The experimental results show that the pulse level parameters could have huge impact to arc characteristic and arc force. With the increased frequency of pulse level, arc plasma has a more obvious pinch effect, which causes the enhance of arc voltage. Similarly, the arc force can be improved obviously compared with that during conventional direct current (DC) TIG welding. By contrast, the sensitivity of welding characteristic to pulse current level frequency would reduce while the duty of pulse peak current increased.

High speed fabrication of absorbance-enhanced micro–nanostructures on nickel surface using hundred-nanosecond pulsed laser

2016 ◽  
Vol 56 (1) ◽  
pp. 010305 ◽  
Author(s):  
Jinxiang Fu ◽  
Jingyuan Zhang ◽  
Hao Liang ◽  
Yibo Wang ◽  
Zhiyan Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Pulsed Laser ◽  
Nickel Surface ◽  
Nanosecond Pulsed Laser

Synthesizing Cubic Diamond Crystal Using DC Plasma Jet CVD

2019 ◽  
Vol 825 ◽  
pp. 71-76
Author(s):  
Hiromichi Toyota ◽  
Xia Zhu ◽  
Ryoya Shiraishi ◽  
Kazuto Nakajima ◽  
Yukiharu Iwamoto ◽  
...  
Keyword(s):  
High Speed ◽  
Catalytic Effect ◽  
Plasma Jet ◽  
Methanol Solution ◽  
Arc Plasma ◽  
Plasma Power ◽  
Experimental Conditions ◽  
Diamond Crystals ◽  
Dc Arc ◽  
Solution Gas

Diamond crystals are successfully synthesized by irradiating DC arc plasma jet to the substrate set in a methanol solution. It is the important procedure to preheat the substrate by inert Ar plasma jet before introducing the methanol solution gas to the plasma jet gun. The effects of two experimental conditions, the incident power and the substrates, are investigated. In the case of the Si substrate, cubic crystalline diamond grains of same size are synthesized at the plasma power of 470W. High speed hetero epitaxy is expected by using this method. In the case of the tungsten carbide substrate, diamond crystals and carbon nanotubes are simultaneously synthesized at the plasma power of 260W. The catalytic effect of Co binder in the substrate may cause the chemical reaction of the nanotube synthesis.

A Piezoelectric Droplet Generating Device for Experiment in Successive Droplets Impacting Onto Solid Surface

2018 ◽  
Author(s):  
Jianxin Li ◽  
Huang Zhang ◽  
Yuzheng Li ◽  
Qianfeng Liu ◽  
Hanliang Bo
Keyword(s):  
Solid Surface ◽  
High Speed ◽  
Experimental Studies ◽  
Structure Design ◽  
Nozzle Diameter ◽  
Signal Frequency ◽  
Duty Ratio ◽  
Droplet Generator ◽  
Uniform Size ◽  
Drop On Demand

The outcomes of successive droplets impacting onto solid surface of the steam separator in a nuclear power system’s steam generator has a strong effect on the separating efficiency. Due to amounts of influencing factors, experimental research is an important method to study the phenomena of droplet-wall collision. However, because it is hard to generator continuous droplets with controllable uniform size and frequency, experimental studies about successive droplets impacting on solid surface are relative limited. In this study, a novel drop-on-demand (DOD) droplet generator is designed and fabricated based on piezoelectric ceramics, in which successive droplets with a uniform diameter can be generated. Firstly, the structure design of the DOD droplet generator, the setup of the control system and working principle are described in detail in this paper. Then the droplet generating performance of the device under different signal frequency fs, signal amplitude U, duty ratio Dr, and nozzle diameter Dn are investigated experimentally using a high-speed camera at 4000 fps. Finally, the influence of the signal frequency fs, voltage U, duty ratio Dr and nozzle diameter Dn on the diameter of droplet Dd is discussed. A test of successive droplets generated by the device impacting on an aluminum plate is conducted.

scholarly journals Optimization and Experimental Study of the Semi-Closed Short-Gap Arc-Extinguishing Chamber Based on a Magnetohydrodynamics Model

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3335 ◽  
Author(s):  
Wenbin Jia ◽  
Wenxia Sima ◽  
Tao Yuan ◽  
Ming Yang ◽  
Potao Sun
Keyword(s):  
High Speed ◽  
Basic Structure ◽  
Optimization Method ◽  
Original Structure ◽  
Arc Plasma ◽  
Zero Crossing ◽  
In Series ◽  
Power Frequency ◽  
Motion Characteristics ◽  
Current Zero

The multi-chamber arc-extinguishing structure (MAS), which consists of a lot of semi-closed short-gap arc-extinguishing chambers (SSAC) in series, can be used in parallel gap lightning protection devices to improve the ability to extinguish power frequency follow current. The arc-extinguishing ability of single SSAC directly affects the arc-extinguishing performance of the whole MAS. Therefore, the arc-extinguishing performance of MAS can be improved by optimizing single SSACs. A two-dimensional model of the arc plasma in a SSAC is built based on the magneto-hydrodynamic (MHD) theory. The motion characteristics of an arc in the SSAC are simulated and analyzed. An optimization method of the SSAC structure is proposed. Finally, an impact test platform is built to verify the effectiveness of the optimized SSAC structure. Results show that the short-gap arc forms a high-speed airflow in the SSAC and the arc plasma sprays rapidly to the outlet until the arc is extinguished at its current zero-crossing point. The amplitude of airflow velocity in the optimized structure can be increased to about 8-fold the velocity in the basic structure. Experiments also show that the dissipation time of an arc in the optimized SSAC is 79.2 μs, which is much less than that in the original structure (422.4 μs).

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