Influence of Residual Stresses on the Hardness Number in the Affected Layer Produced by Shot Peening

Author:  Dr. Katsuji Tosha
Source:  The Shot Peener magazine, Vol 19 / Issue 1, Winter 2005
Doc ID:  2005015
Year of Publication:  2005
Abstract:  
ABSTRACT The hardness is a resistance for the local plastic deformation producing the stress field itself. The hardness number, therefore, is affected by applied or residual stresses. In order to clarify the influences of residual stresses on the hardness numbers quantitatively, shot peening and sheet bending were performed for a medium carbon steel (C: 0.45 %). Hardness and residual stress measurements were made using a micro-Vickers hardness tester and a X-ray diffractometer respectively. The following results are obtained; (1) Hardness numbers increase in the compressive stress field induced by shot peening. (2) The maximum hardness increment was 13 HV in the compressive stress field. (3) The influences of compressive residual stresses induced by shot peening on the hardness number are similar to the case of sheet bending.