Comparison of Properties and Bead Geometry in MIG and CMT Single Layer Samples for WAAM Applications

Harley Stinson,Cormac Mcgarrigle,Justin Quinn,Richard Ward

doi:10.3390/met11101530

Abstract

The process of Wire Arc Additive Manufacturing (WAAM) utilizes arc welding technology to fabricate metallic components by depositing material in a selective layered fashion. Several welding processes exist that can achieve this layered deposition strategy. Gas Metal Arc Welding (GMAW) derived processes are commonly favored for their high deposition rates (1–4 kg/h) and minimal torch reorientation required during deposition. A range of GMAW processes are available; all of which have different material transfer modes and thermal energy input ranges and the resultant metallic structures formed from these processes can vary in their mechanical properties and morphology. This work will investigate single-layer deposition and vary the process parameters and process mode to observe responses in mechanical properties, bead geometry and deposition rate. The process modes selected for this study were GMAW derived process of Metal Inert Gas (MIG) and Cold Metal Transfer (CMT). Characterization of parameter sets revealed relationships between torch travel speeds, wire feed speeds and the specimen properties and proportions. Differences were observed in the cross-sectional bead geometry and deposition rates when comparing MIG and CMT samples though the influence of process mode on mechanical properties was less significant compared to process parameter selection.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The results from specimens across the parameter sets show the hardness values (Hv) respond to the calculated values of Heat Inputs (HI) in each parameter set with inverse proportionality
The influence of parameter settings on the hardness values seen in test samples was more pronounced than that of process mode alterations between Cold Metal Transfer (CMT) and Metal Inert Gas (MIG)

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The use of WAAM for metals is attracting attention from researchers and the industry for its potential productivity associated with its highly efficient material utilization, energy consumption and high deposition rates when compared to powder-fed additive manufacturing techniques [1]. GMAW based WAAM has the potential to obtain the highest material deposition rates (1–4 kg/h) whilst maintaining geometric accuracy of approx. 2 mm minimum feature size and minimal presence of defects. A variety of GMAW derived processes are available from welding equipment manufacturers, providing a range of techniques to control thermal energy inputs and minimize undesirable process defects such as, spatter and loss of melt pool stability during deposition.

Results

Discussion

Conclusion