Gamma (γ) phase transformation in pulsed GTAW weld metal of duplex stainless steel

Studies on weldability of iron-based powder metal alloys using pulsed gas tungsten arc welding process

“…In contrast to continuous current welding, in the pulsed mode the heat energy required to melt the base material is supplied only during peak current pulses for brief intervals of time allowing the heat to dissipate into the base material. As a consequence the heat input to the welding is decreased resulting in a narrower HAZ with reduced residual stress and distortion (Wang et al, 2006;Kumar et al, 2007). Moreover, the use of pulsed current on conventional mode has been associated with a finer structure due to an increase of the melt pool agitation and greater strength weldments under impact loading (D'Oliveira et al, 2006;Wang et al, 2006;Kumar et al, 2007).…”

“…As a consequence the heat input to the welding is decreased resulting in a narrower HAZ with reduced residual stress and distortion (Wang et al, 2006;Kumar et al, 2007). Moreover, the use of pulsed current on conventional mode has been associated with a finer structure due to an increase of the melt pool agitation and greater strength weldments under impact loading (D'Oliveira et al, 2006;Wang et al, 2006;Kumar et al, 2007). Also, studies have shown that the combination of welding parameter, shielding gas and content of the filler metals with lower heat input, refinement of grains can be obtained.…”

Weldability of Iron Based Powder Metal Alloys Using Pulsed GTAW Process

“…As a result of all mentioned above, it is possible to obtain weldments with a narrower HAZ as well as reduction of segregation of alloying elements, of residual stress and of the hot cracking sensitivity (D' Oliveira et al, 2006;Wang et al, 2006). Current pulsing also results in periodic variations of the arc forces and in an increase of the melt pool agitation leading to additional fluid flow, which lowers the temperature in front of the solidifying interface.…”

Analysis of Design of Experiments Methodology for Optimization of Pulsed Current GTAW Process Parameters for Ultimate Tensile Strength of UNS S32760 Welds

“…Pulsed current gas tungsten arc welding (PCGTAW), developed in the 1950s, is a joining technology, which is a variant of the constant current gas tungsten arc welding (CCGTAW) process utilized in a wide range of applications [5,6]. The PCGTAW involves cycling of the welding current from a high to a low level at a selected regular frequency.…”