Effects of arc current and travel speed on the processing of stainless steel via wire arc additive manufacturing (WAAM) process

Abstract

Wire Arc Additive Manufacturing (WAAM) is an additive manufacturing process that uses an electric arc as the heat source to melt the feed metal wire and deposit it as per the desired 3D shapes. The current study investigates the influence of critical process parameters, namely welding current and travel speed, on the bead geometry and microstructure of deposits of stainless steel (308L). The results reveal that higher welding currents lead to increased bead width, while travel speed inversely affects bead height. Moreover, contact angles between the deposited material and the substrate increase with the welding current. An analysis of the liquid-to-vapor transition (δ) highlights its correlation with travel speed, impacting the spreadability of the deposited material. Notably, among all tested combinations of current and travel speed, 120 A and 25 mm/min yield uniform layer deposition of 308L stainless steel wire, an ideal outcome for WAAM applications. Additionally, it was observed that the percentage of the ferrite phase within the deposited material’s microstructure exhibits an intriguing relationship, increasing with travel speed while decreasing with rising current and layer number. These findings offer valuable insights into process optimization for WAAM-based orthopedic applications, emphasizing the potential for customized orthopedic knee implants with improved quality and performance.

Keywords:

• Additive manufacturing
• high energy deposition
• contact angle
• surface energy
• WAAM
• 3D printing
• implants
• energy consumption

Acknowledgements

The authors also thank Dr. Niranjan N Chiplunkar, Principal NMAMIT affiliated with Nitte (Deemed to be) University, Nitte, and Nitte management for supporting this study by providing all the needed resources.

Author contributions

Dr. Vijeesh V conceived the idea of processing stainless steel material using the WAAM method and presented the idea to Dr. Rajath N. Rao, Dr. Manjunath Maiya, and Dr. Vishwanatha H. M. All the authors carried out the literature review to arrive at the latest happenings in the field and contributed with various inputs for further strengthening of the concept and drafting of the experimental setup was initiated by Vijeesh. Funding for the work was supported by the funded research project supervisioned by Vijeesh. While developments of the WAAM setup at Vijeesh’s lab were in progress, the objectives of the work were further fine-tuned to primarily focus on the process parameters. In this regard, inputs were sought from Dr. Pawan Kumar, Dr. Nakul Gupta, Dr. Kuldeep K. Saxena, and Dr. Vishwanatha H. M. In the meantime, Vijeesh came up with a novel idea of exploring the concept of WAAM towards printing bio-medical implants and proposed the idea to the team. He explained the concept of attempting the printing of stainless steel using WAAM. The team was excited by the idea and added various inputs. Pawan Kumar suggested varying the process parameters in addition to the few modifications in the experimental setup. All the initial experiments were conducted by Rajath N. Rao and Manjunath Maiya. The initial findings were analyzed by all the authors. Further, Kuldeep K. Saxena and Nakul Gupta expressed the opinion of optimization of a few critical process parameters like current and speed of deposition. In addition, Vijeesh came up with another novel thought of studying the contact angle effects of the deposited material with varied speeds and currents. Accordingly, optimization was carried out by Vijeesh and he also considered studying the effect of the optimized parameters on the microstructure. Pawan Kumar and Vishwanatha H. M. also opined on the consideration of process-structure correlations. Accordingly, Vijeesh and Vishwanatha H. M. initiated the microstructural studies. The results were analyzed by Vishwanatha H. M., Rajath Rao, Manjunath Maiya, and Vijeesh. Pawan Kumar gave further insights on the microstructural analysis. In the same line, Kuldeep K. Saxena added further interpretations to the optimized process parameters and their effect on the microstructure. Based on the discussions, the initial draft was prepared by Vishwanatha H. M. and Pawan Kumar. All authors opined on the initial version and further editing was carried out by Vishwanatha H. M. With paramount efforts, the final version was made by Dr. Vijeesh V and all authors agreed upon for publishing the article. All authors agree to be accountable for all aspects of the work.

Disclosure statement

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

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The authors thank AICTE for providing financial assistance under the Research Promotion Scheme [AICTE-RPS project—File No. 8-110/FDC/RPS (POLICY-1) 2019-20, Dated 14 August 2020] to procure/fabricate the equipment needed for this study.