The Effect of Severe Shot Peening on Fatigue Life of Laser Powder Bed Fusion Manufactured 316L Stainless Steel

Timo Rautio; Matias Jaskari; Tejas Gundgire; Terho Iso-Junno; Minnamari Vippola; Antti Järvenpää

doi:10.3390/ma15103517

The Effect of Severe Shot Peening on Fatigue Life of Laser Powder Bed Fusion Manufactured 316L Stainless Steel

Materials (Basel). 2022 May 13;15(10):3517. doi: 10.3390/ma15103517.

Authors

Timo Rautio¹, Matias Jaskari¹, Tejas Gundgire², Terho Iso-Junno¹, Minnamari Vippola², Antti Järvenpää¹

Affiliations

¹ Kerttu Saalasti Institute, University of Oulu, Pajatie 5, 85500 Nivala, Finland.
² Materials Science and Environmental Engineering, Tampere University, 33014 Tampere, Finland.

Abstract

Severe shot peening (SSP) was used on additive manufactured 316L by laser powder bed fusion. The effect of the post processing on the surface features of the material was analyzed through residual stress measurements, tensile testing, hardness-depth profiles, and fatigue testing by flexural bending. The results showed that SSP can be utilized to form residual stresses up to -400 MPa 200 μm below the surface. At the same time, a clear improvement on the surface hardness was achieved from 275 HV to near 650 HV. These together resulted in a clear improvement on material strength which was recorded at 10% improvement in ultimate tensile strength. Most significantly, the fatigue limit of the material was tripled from 200 MPa to over 600 MPa and the overall fatigue strength raised similarly from a low to high cycle regime.

Keywords: 316L; bending fatigue; laser powder bed fusion; severe shot peening.

Grants and funding

This research was funded by the European Union (European Regional Development Fund, Council of Oulu Region) for the “Hybridi” Grant Nos. A73071 and “M3D” Grant No. A77901, and by Association of Finnish Steel and Metal Producers, Grant No. 750.