Jiaxiang Xue

Gaussian Pulsed Current Waveform Welding for Aluminum Alloys

A new welding method, which uses a Gaussian current waveform with a smooth curve and concentrated energy input, was applied for welding of aluminum alloys of various thickness. Current peak modulation and base modulation models are proposed in the article. Five welding experiments were carried out using ER4043 1.2 mm aluminum wire, the results showing that the welding process was found to be stable, and that current and voltage waveforms were regular with no broken arcs or short circuits. Moreover, the arc voice sound was soft with low splatter. Weld seam surfaces were bright with regular scaly stripes and proper weld height and penetration.

Sample Entropy-Based Approach to Evaluate the Stability of Double-Wire Pulsed MIG Welding

According to the sample entropy, this paper deals with a quantitative method to evaluate the current stability in double-wire pulsed MIG welding. Firstly, the sample entropy of current signals with different stability but the same parameters is calculated. The results show that the more stable the current, the smaller the value and the standard deviation of sample entropy. Secondly, four parameters, which are pulse width, peak current, base current, and frequency, are selected for four-level three-factor orthogonal experiment. The calculation and analysis of desired signals indicate that sample entropy values are affected by welding current parameters. Then, a quantitative method based on sample entropy is proposed. The experiment results show that the method can preferably quantify the welding current stability.

Effect of Thermal Frequency on AA6061 Aluminum Alloy Double Pulsed Gas Metal Arc Welding

The present investigation aims to contrast the effect of the commonly used thermal frequency on welding process suitability, weld profile, weld macrostructure, and weld hardness on AA6061 aluminum alloy double pulsed gas metal arc welding. Material manufacturing processes and welding parameters with thermal frequencies of 2, 3, and 4 Hz are described in detail. Three defect-free welds were successfully formed at these thermal frequencies. The results indicate the following: (1) thermal frequency has no effect on welding process suitability when the welding parameters are self-matching; and (2) at increased thermal frequency, weld ripple distance reduces, maximum penetration depth decreases, grain size of the fusion zone decreases, and fusion zone hardness increases.

Effect of Current Phase on Tandem Wire Pulsed MIG High-Speed Welding

Magnetic field distribution model of tandem wire pulsed MIG high-speed welding was established, so was model of electromagnetic force on droplet. Through analyzing on parameters of the magnetic field of arc space, it was found that magnetic field intensity generated by arc and current were linear dependence, when current pulses of tandem wire were not overlapped, magnetic blow caused by parallel arc was minimum. Through analyzing on parameters of the model of electromagnetic force on droplet, it was found that the unit electromagnetic force on droplet and current product of the tandem wire were linear dependence, when the current pulses of tandem wire were not overlapped, the electromagnetic force on droplet was the least, and deviate distance of droplet trajectory was also minimum. Finally, contrast experiments of in-phase, random-phase and anti-phase current pulse were carried out by self-developed multifunctional tandem wire welding machine. The results indicated: when the current pulse of leading torch and tracking torch were not overlapped, the welding process was stable, and the weld was perfectly formed.