Microstructure characterization of SS308LSi components manufactured by GTAW-based additive manufacturing: shaped metal deposition using pulsed current arc

Abstract

Shaped metal deposition method using gas tungsten arc welding is a novel manufacturing technology that can be used for fabricating solid dense parts in layered manufacturing. This paper reports for the first time using the pulsed current shaped metal deposition technique for fabricating components using cold wire of AISI 308LSi stainless steel. The aim of this work was to investigate and compare the effect of pulse frequency and other deposition process parameters on the morphology aspects and microstructure characteristics of the manufactured components using pulsed and continuous current processes. The obtained results reveal that the structure of the deposited specimens produced via pulsed arc current is generally having finer grains, high residual ferrite, and absence of columnar grains. Pulse frequency and current ratio have a significant influence on the surface morphology and microstructure of the manufactured parts. Good metallurgical bonding with no sensitization effects can be seen in all tested specimens. The presented additive layered manufacturing method can be recommended for near netshaped processing of austenitic stainless steel components, and it can be used as an alternative manufacturing method for fabricating metal components with free defects, higher corrosion resistance, and superior mechanical properties.

Grain refinement in an unalloyed tantalum structure by combining Wire+Arc additive manufacturing and vertical cold rolling

“…WAAM can directly fabricate fully-dense metallic large 3-D near-net-shape components with a much higher deposition rate, than most other metal additive manufacture processes [5,6], the highest rate so far being of 9.5 kg/h [7]. The WAAM process has successfully produced large-scale parts in stainless steel [8], Inconel ® [9], titanium [10], aluminium [11] and tungsten [12]. Furthermore, functionally graded structures of refractory metals have also been deposited using WAAM [13].…”

Development of a novel TIG hot-wire process for wire and arc additive manufacturing

“…This makes it possible to ignite the arc independently of the filler material supply by means of highfrequency or drawn arc ignition, which facilitates a stable, spatter-free starting process. TIG hot wire processes are mainly used in the additive production of highly reactive materials such as high-alloyed steels as well as titanium and nickelbased alloys [22][23][24][25][26][27][28][29][30]. However, a striking disadvantage of processes with a non-melting electrode is that the torch is set vertically with a lateral hot wire feeding system.…”

Tandem metal inert gas process for high productivity wire arc additive manufacturing in stainless steel

“…Previous studies on WAAM of stainless steel report the use of Gas Tungsten Arc Welding (TIG) for 308LSi steel, Cold Metal Transfer (CMT) for 240 steel [4], CMT and automated TIG welding (Top TIG) for stainless steel with the aim of optimizing deposition rate [5] and deposition strategies for any material [6]. An attempt to reach high productivity has been reported by Yuehai Feng [7] using double wire plasma arc in comparison with single wire with good results Queguineur, A. et al analyse the potential of additive manufacturing for large components using the CMT process and the consequences on the manufacturing time for austenitic stainless steel parts used in naval construction [8].…”