Relations of Compressive Residual Stress on Prestressed Surfaces Submitted to the Stress Shot Peening Process in EN 47 Spring Steel

This work deals with different stress shot peening conditions’ effects on the compressive residual stress intensity and distribution. The tests were conducted on 15 mm x 70 mm x 1500 mm bars made of quenched and tempered EN 47 spring steel (DIN 51CrV4). Tensile tests and microstructure analysis were applied to guarantee the specification regarding resistance and microstructure. The stress shot peening process was conducted in an unloaded sample and two points bending loading with support distances of 150 and 1000 mm. The maximum flexural tension stresses were 750 and 1500 MPa for the two support distances. The residual stresses were measured by X-ray diffraction in five positions: measurements of samples with deflections were made without deflection, and a total of 95 residual stress measurements were performed before blasting. The compressive residual stresses increased as the calculated loading increased for all test conditions. Otherwise, for the 1000 mm support distance for the higher loading condition, the pre-tension calculated by the ANSYS™ showed higher flexural tension stress in the support position, while the residual stresses were constant between the supports.

Keywords:
Shot peening; stress shot peening; residual stress