Arc characteristics and weld formation of aluminum alloy by AC/DC mixed GTAW

ABSTRACT

The purpose of the method of AC/DC mixed gas tungsten arc welding (GTAW) is to improve the welding efficiency of aluminum alloy AC-GTAW. It is expected to make a great change in the aluminum alloy manufacturing industries. The feature of AC/DC mixed GTAW includes two parts, AC mode and DC mode, during the welding process. A comparison study between the AC/DC mixed GTAW and AC-GTAW is carried out by analyzing the arc characteristics and weld formation. The results showed that the uniformly distributed AC and DC signals were obtained in the AC/DC mixed GTAW. The front width and back reinforcement of the weld bead in the AC GTAW and the AC/DC mixed GTAW increased first and then decreased with increasing frequency. The geometrical parameters of the weld cross-section in the AC/DC mixed GTAW was increased, when the same frequency was used. For example, the frequency of 30 Hz was employed, the front width of the weld bead in the AC/DC mixed GTAW was increased to 0.3 mm compared with that of the AC-GTAW. The AC/DC mixed GTAW has a greater effective heat input compared with the AC GTAW due to introduction of the DC mode.

KEYWORDS:

• AC/DC
• mixed
• GTAW
• arc
• characteristics
• weld
• formation
• aluminum
• alloy

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