Mechanical, metallurgical, and corrosion investigations on wire arc additively manufactured low carbon steel

Abstract

Current global 3D metal printing research is focused on powder bed fusion and direct energy deposition. Several materials are presently under research to assess their post-additive manufacturing properties, and to process them in industries using advanced manufacturing techniques. This study investigates the electrochemical, mechanical, and metallurgical properties of wire arc additively manufactured (WAAM) ER70S-6 alloy walls on AISI S235 plates, emphasizing ship component fabrication. The corrosion resistance of both materials is assessed through Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization testing in a 3.5% NaCl solution. Surface and cross-sectional morphologies are analyzed using optical microscopy and scanning electron microscopy, while energy dispersive spectroscopy is employed to study the chemical composition of the corrosion products. Moreover, the hardness of the WAAM-deposited ER70S6 wall is found to be highest in the uppermost layers of deposition due to the presence of acicular ferrite and ferritic-bainite microstructure. Tensile and Charpy impact strength for AISI S235 and WAAM-deposited ER70S-6 exhibit similar performance at room and low temperatures. Interestingly, the WAAM sample demonstrates a 60% higher elongation than the AISI S235 sample. Hence, the findings from this experimental work suggest that WAAM-deposited carbon steel exhibits favourable corrosion resistance and comparable mechanical properties to AISI S235. Consequently, WAAM is emerging as a promising alternative to conventional manufacturing techniques for fabricating ship components, repairing and modifying hull structures, manufacturing nozzles, propeller blades, fin-like structures, structural components, and more.

Keywords:

• Wire arc additive manufacturing
• electrochemical impedance spectroscopy
• corrosion analysis
• surface roughness
• low-temperature toughness
• tensile strength
• SEM and EDS

Acknowledgements

The support of the School of Mechanical Sciences and Centre of Excellence in Particulates, Colloids and Interfaces at the Indian Institute of Technology Goa for WAAM depositions, materials characterization, mechanical testing, and electrochemical testing is gratefully acknowledged. We would especially like to thank Prof. Bidhan Paramanick for his constant and selfless support during SEM and EDS analysis of the samples. We are also thankful to Shri Naresh Mandal for his help during corrosion testing.

Ethical approval

Not applicable.

Consent for publication

All the authors agreed to publish this paper.

Author contributions

All authors of this paper have contributed, read, and approved the final submitted version.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Code availability statement

Not applicable.

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared as the data also forms part of an ongoing study.

Additional information

Funding

Thanks to IIT Goa Research Funding for Robotic MIG setup and consumable materials.