Thermal and Weld Bead Characteristics of Bead-on-Plate PGMA Welding of Dissimilar ASS Bead on HSLA Plate

Abstract

The research work has focused on identifying the influence of pulsed gas metal arc welding (PGMAW) parameters on the austenitic stainless steel (ASS) weld bead on high-strength low-alloy (HSLA) steel plate. The effect of pulse parameters such as dimensionless factor (ϕ), mean current (Im), and heat input (Ω) has been analyzed on the thermal behavior of weld, weld pool geometry, and the weld bead microstructure. The influence of ϕ on the thermal and metal transfer behaviors has been also examined to produce the desired weld bead quality. The optimized pulse parameters such as Im (160–230 A), Ω (6.5–11.2 kJ/cm), ϕ (0.05–0.25), and welding speed (S) (15–25 cm/min) have been considered to perform the experiment. The microstructural evaluation of the weld bead was carried out by an optical microscope. The enhanced Im from 160 A to 230 A considerably increased the amount of temperature received by the weld pool (QT) from 4525 to 6525 J/S. The results also depicted that the increase of ϕ from 0.05 to 0.25 predominantly reduced the width of the weld bead (Wb) from 15 to 13.5 mm, depth of penetration (Pd) from 3.5 to 2.5 mm, and area of fusion (Af) from 40 to 30 mm2, respectively. It is also found that the formation of fine-grain microstructure in the weld deposit primarily happened due to the effect of thermal behaviors such as QT, transfer of heat content from filler to weld pool (Qf), and characteristics of filler metal transfer to the weld deposition.