The Development of Residual Stresses and Curvature in Mild Steel by Needle Peening

Author:  David Kirk
Source:  Conf Proc: ICSP-6, (p.312-319)
Doc ID:  1996079
Year of Publication:  1996
This study has involved a bench-mounted, air driven, needle gun with 2 mm diameter flat-ended needles, to apply controlled peening to 3 mm and 6 mm thick mild steel specimens. The induced curvature increased with both air pressure and peening time. Radii of curvature approaching 400 mm and 1600mm were abtained for the 3 mm and 6 mm thicknesses respectively. Needle peening also induced substantial levels of compressive surface residual stress (-200 MPa) but not as high asd those induced by shot peening of the same material (-251 MPa). It has been concluded that needle peening could have useful commercial applications for both residual stress development and peen forming.

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