Accuracy of X-ray diffraction measurement of residual stresses in shot peened titanium alloy samples

Accuracy of residual stress measurement using the Sin^2 ψ method has become a focus in many applications where residual stress plays a critical role in components, such as aeronautics, railway welding, bearings, gears, etc. Accuracy in residual stress measurement requires consideration of both correctness and uncertainty. In this paper, a self-designed and home-made in-situ tension/compression device is adapted to evaluate the correctness of residual stress measurement in titanium alloy. A calculation method employing multiple convolutions to evaluate the uncertainty of residual stress measurement is presented. Test results show that the X-ray elastic constant is an important parameter impacting the correctness of residual stress measurement. And that the uncertainty of residual stress measurement fluctuates with the surface status of shot peened samples.