Effect of Active Gas on Weld Shape and Microstructure of Advanced A-TIG-Welded Stainless Steel

Abstract

Advanced A-TIG method was conducted to increase the weld penetration and compared with the conventional TIG welding process. A two-pipeline setup was designed to apply Ar ? CO 2 mixed gas as the outer layer, while pure argon was applied as the inner layer to prevent any consumption of the tungsten electrode. The results indicate that the presence of active gas in the molten pool led to the change in the temperature coefficient of surface tension so that the Marangoni convection turns inward and forms a deep weld zone. The increase in gas flow rate causes a decrease in the weld efficiency which is attributed to the increase in oxygen content in the weld pool and the formation of a thicker oxide layer on the weld surface. Moreover, the stir and the temperature fluctuation, led by double shielding gas, create more homogeneous nucleation sites in the molten pool so that a fine grain microstructure was obtained.

Non-Destructive X-ray Characterization of a Novel Joining Method Based on Laser-Melting Deposition for AISI 304 Stainless Steel

“…It can be attributed to the increase in argon content in the weld pool and the formation of a thick protective layer on the weld surface, reducing the WD. These findings are in good correlation with the one provided in Reference [24]. The data trend can be analyzed via a curve fitting, as shown in Figure 5.…”

Haz Formation And Analysis In Flux Assisted Gtaw

“…After welding, the weld beads were sectioned and the specimens for metallographic testing were prepared by grinding and polishing the specimen. Etching was done by dipping the specimen in a solution of HCl, CuSO4 and distilled water [21]. The weld bead cross-sections were photographed by Leica Microscope at different magnifications.…”

Influence of inconel interlayer on microstructural, mechanical and electrochemical characteristics in single-pass ATIG welding of dissimilar austenitic and duplex stainless steel

“…Activated flux is applied to the plate in a thin layer prior to welding in this method. The inclusion of this activated flux is thought to improve the weld's penetration, raising the TIG welding process's overall quality and efficiency [1,2]. With the aid of active metallic powders, an arc is formed between a non-consumable tungsten electrode and a workpiece during the gas-shielded arc welding method known as ATIG.…”