Residual Stresses Induced by Peening Austenitic Ductile Cast-Iron

Author:  D Kirk, D G Birch
Source:  Conf Proc: ICSP-7 (pg 23-32)
Doc ID:  1999012
Year of Publication:  1999
Abstract:  
Beneficial compressive surface residual stresses have been induced by peening an austenitic ductile cast iron (20%Ni, 2%Cr, 0.15%Nb weldable-grade). Stress levels of -433MPa and -280MPA were found for shot-peened and needle-peened conditions respectively. Surface compressive residual stresses of that magnitude will impart substantial improvements to the service performance of castings. Stress measurements were made using a standard two-exposure X-ray diffractometer technique. Young's modulus and Poisson's ratio measurements, needed to convert measured strains into stresses, were made using tensile-loaded strain-gauged specimens. Isochronal annealing experiments showed that a large proportion of the induced compressive residual stress could be retained up to 450