Relationship Between Coverage and Surface Residual Stress

Author:  D. Kirk and R. C. Hollyoak
Source:  Conf Proc: ICSP-9 (pg 373-378)
Doc ID:  2005112
Year of Publication:  2005
Abstract:  
ABSTRACT Controlled, uniform, peening has been used to impose precise coverage percentages onto mild steel plate specimens. This was achieved by using an X-Y table to move the specimens under a single, precision-loaded, 2mm diameter indenter. X-ray studies have revealed a surprising relationship between percentage coverage and surface residual stress. Stress increases almost linearly with low coverages but reaches a maximum at about 80% coverage. At 100% coverage the induced compressive surface residual stress is about 20% lower than at the maximum. The as-received steel plate contained a low level of tensile surface residual stress. The maximum surface stress of about -350MPa is well above the tensile test yield strength for mild steel. Traverses were carried out at 90