SYMPOSIA PAPER Published: 26 February 2022
STP163720200131

Influence of Stress Gradient, Specimen Type, and Surface Roughness on Fatigue Behavior of Additively Manufactured 17-4 PH Stainless Steel

Source

The effects of stress gradient resulting from a different type of loading condition (i.e., rotating-bending [R-B] versus axial), specimen (i.e., hourglass for R-B versus round with straight gage section for axial), and surface roughness on the fatigue behavior of 17-4 precipitation hardening stainless steel fabricated using the laser beam powder bed fusion process are investigated. Fatigue experiments are conducted on specimens with as-built and machined/polished surface conditions. For the as-built surface condition, the fatigue resistance of laser beam powder bed fusion 17-4 precipitation hardening stainless steel specimens under R-B and axial loadings are found to be comparable at all stress levels, and fatigue cracks are all observed to initiate from the micronotches at the surface. Similarly, cracks in the R-B and axial specimens in a machined/polished surface condition are also observed to initiate from the volumetric defects. However, the defect size in the R-B specimens is consistently smaller and, consequently, results in better fatigue resistance as compared to the axial specimens. Hence, special care needs to be taken during the specimen design to ensure that there is enough volume of material at the gage section to correctly capture the porosity level within the material.

Author Information

Shrestha, Rakish
Dept. of Mechanical Engineering, Auburn University, Auburn, AL, US National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, US
Nezhadfar, P.
Dept. of Mechanical Engineering, Auburn University, Auburn, AL, US National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, US
Simsiriwong, Jutima
National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, US School of Engineering, University of North Florida, Jacksonville, FL, US
Shamsaei, Nima
Dept. of Mechanical Engineering, Auburn University, Auburn, AL, US National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, US
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Pages: 282–295
DOI: 10.1520/STP163720200131
ISBN-EB: 978-0-8031-7722-2
ISBN-13: 978-0-8031-7721-5