Effect of Fast-Frequency Pulsed Current Parameters on FFP-TIG Arc Behavior and Its Implications for Inconel 718 Welding

Tungsten inert gas (TIG) is currently one of the most widely applied welding technologies. However, the arc energy divergence and high heat input of conventional TIG can lead to welding defects in heat-input-sensitive alloys (such as Inconel 718). Introducing a fast-frequency pulsed current (≥20 kHz) in TIG creates a welding process named fast-frequency pulsed tungsten inert gas (FFP-TIG). The arc behavior of FFP-TIG has advantages over conventional TIG in terms of arc contraction, arc pressure, and energy density. With an increase in the FFP current amplitude or frequency, the arc diameter and arc area are reduced, the arc pressure at the center of the arc is increased, and the arc energy divergence and arc temperature are reduced. The FFP-TIG weld method was adapted for Inconel 718 based on FFP-TIG arc behavior. This study provides fresh insight into the development and application of FFP-TIG arc physics research and industrial applications.