The present research work proposes a non-destructive methodology to detect and measure subsurface deformation using Grazing incidence X-ray diffraction (Gi-XRD). The FWHM of the XRD peak that indicates the degree of plastic deformation was measured at different X-ray penetration depths by changing the angle of incidence during Gi-XRD. However, these FWHM values do not represent the actual FWHM at a particular depth because it also captures the effect of the top layers. Therefore, the FWHM values were further analysed to get the actual FWHM for a particular penetration depth and correlated with the deformation depth. The non-destructively measured deformed layer thickness was verified against the results of the metallographic study and a deviation of around 1.2 μm was recorded. © 2021 Elsevier Ltd