Roughness Reduction of Additively Manufactured Steel by Electropolishing

Journal Article · Wed Dec 11 00:00:00 EST 2019 · International Journal of Advanced Manufacturing Technology

DOI:https://doi.org/10.1007/s00170-019-04720-z· OSTI ID:1638686

Tyagi, Pawan  ^[1]; Brent, Denikka ^[1]; Saunders, Tyler ^[1]; Goulet, Tobias ^[1]; Riso, Christopher ^[1]; Klein, Kate ^[1]; Moreno, Francisco Garcia ^[2]

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1. University of the District of Columbia, Washington, DC (United States)
2. Department of Energy's National Security Campus, Kansas City, MO (United States)

Improving surface finishing is the critical step in the application of an additively manufactured (AM) component in high fatigue and corrosion-sensitive fields. This paper provides insights into surface properties of electropolished AM component made up of 316 stainless steel with > 6% carbon. We performed surface analysis with profilometer, scanning electron microscope, and AFM to investigate the electropolished and unpolished AM components. The first major discovery of the present work is that our optical profilometry study provided an estimate of the amount of material to be removed to achieve a shiny and smooth surface on 316 stainless steel AM part. One needs to remove more than 200 μm thick layer from the surface to make a mirror-smooth surface. Such estimation can enable researchers to incorporate requisite tolerance during the design stage itself. The second important finding of our work is that ultrasmooth microstructure on the AM surface appeared when preferential material removal occurred along the boundary of the hexagonal microscopic features. Additionally, our optical profilometry studies provided an analysis of several roughness parameters on the electropolished surface. Electropolishing was effective in reducing the surface roughness below ~ 0.1 μm RMS over microscopic regions. Observation of sub-μm RMS roughness was consistently observed with the optical profilometer, SEM, and AFM. SEM study revealed a significant change in the microstructure of the electropolished samples in a medium and highly smooth state. Here, we also conducted a water contact angle study and spectroscopic reflectance study on electropolished and unpolished AM component surfaces. Our study revealed that electropolishing is a highly promising route for improving the surface finishing of AM components.

• Research Organization: University of the District of Columbia, Washington, DC (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); National Science Foundation-CREST
• Grant/Contract Number: NA0003945; FOA-0003945; HRD-1914751
• OSTI ID: 1638686
• Journal Information: International Journal of Advanced Manufacturing Technology, Vol. 106, Issue 3-4; ISSN 0268-3768
• Publisher: Springer
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Additive manufacturing
roughness
electropolishing
3D printing
SEM