Determination of shot peened surface states using the magnetic Barkhausen noise method

The experiments have been performed on different shot peened sheets of Armco iron and the steel C60. The residual stress (RS) distributions have been determined by the X-ray method and by the bending arrow etching method. From these results, the residual stress distributions of first, second (and third) kind have been evaluated. The nondestructive testing has been carried out using the magnetic Barkhausen noise method. From these Barkhausen noise events which are rectified and recorded over the tangential field strength, different stress and microstructure sensitive quantities have been derived. The most important parameter for these testing procedures is the analyzing frequency. This investigation has shown that shot peened surface states can be characterized by these micromagnetic quantities: especially the homogeneity of shot peened-, the work-hardened profile- and the quantitative (after calibration) residual surface-stress state.