Effect of heat input on microstructure and mechanical properties of stainless steel structures fabricated by wire arc additive manufacturing

Abstract

Additive Manufacturing (AM) as an emerging technology has gained more attention in manufacturing industry that promises higher deposition rate, medium complexity, lower material cost, shorter lead times, materials savings and time to market. In this work an emerging technology of Wire Arc Additive Manufacturing (WAAM) process is used to fabricate the 316L stainless steel walls at various heat input conditions. WAAM process enables the higher deposition rate, material usage, moderate complexity and less cost. The WAAM process has the capability to produce the large scale parts at high deposition efficiency and gaining interest from various industrial sectors. Cold Metal Transfer (CMT) is a modified version of Gas Metal Arc Welding (GMAW) process based on the controlled dip transfer mechanism, accurate shape, low heat input, excellent quality and spatter free. In order to optimize the WAAM deposition process under the influences of various process parameters conditions were evaluated. The various process parameters were identified such as: Weld Current (WC), Wire Feed Speed (WFS) and Travel Speed (TS) on weld bead geometry has been also explored. Parameters ranges were identified by based on conducting the trial and error experiments. Primarily, the 316L stainless steel walls were fabricated with various heat input using CMT-WAAM process under the manual mode, According to the results obtained, it suggests that the 316L deposit thin walls cannot be convinced in manual mode with respective to dimension accuracy, control, number of wastages, quality and performances of the part. Initially the bead on plate experiments were conducted to identify the heat input levels, secondly the suitable various heat input condition was selected to fabricate 316L stainless steel thin walls using automatic CMT-WAAM process. newline