Non-destructive testing methods
Residual stresses can be measured non-destructively with X-ray diffraction method. X-ray diffraction provides reliable and objective data for quality control assessment.
X-rays have high energy and short wavelength when compared to visible light making them ideal for probing the interplanar distances (=residual stress) in crystalline materials.
Barkhausen noise analysis is a non-destructive method involving the measurement of a noise like signal induced in a ferromagnetic material by an applied magnetic field.
There are two main material characteristics that will directly affect the intensity of the Barkhausen noise signal: hardness and stress.