[en] The economic and scientific importance of neutron diffraction residual stress analysis has led to an increasing number of suitable instruments worldwide. Recently, a dedicated state-of-the-art diffractometer has been installed at the National Institute of Standards and Technology reactor. It has been used for a variety of measurements on basic and engineering stress problems. Among the most prominent examples that have been investigated are residual stresses in rails, weldments, and plasma-sprayed coatings

[en] Fueled by pressures to reduce scrap and tooling costs, the modeling and prediction of springback has become a major focus of interest in sheet metal forming. Finite element codes and packages are being developed or improved but face the demand for higher predictive accuracy which, in turn, requires accurate property data and a more complete understanding of the stresses that are responsible for the elastic part of the springback. In order to provide experimental data for these calculations, synchrotron X-ray diffraction measurements were carried out in order to determine the through-thickness distribution of axial and tangential residual stresses in an Al6022 deep drawn cup. The technique is able to provide true spatial resolutions of 0.05 mm for a strain measurement on a cup with 0.92 mm wall thickness. It is found that both axial and tangential stresses exhibit non-linear gradients through thickness and both exhibit a pronounced dependency on the axial position. The springback measured on a split ring cut from the cup agrees within 3% accuracy with the value predicted from the average of measured through-thickness stresses

[en] The residual stresses created by deep drawing of AISI-1010 cups were investigated by means of neutron diffraction. The wall thickness of the cups was below 3.0 mm, for which 8-10 through-thickness measurements were conducted. It was found that the axial, and tangential stress profiles are similar to what is expected from a bending-unbending operation, but it also exhibits a strong dependence on the axial and, to a minor extent, on the circumferential position. The strong axial stress dependence reflects the effect of stretching while the weaker circumferential stress variations are due to sheet anisotropy. We also found that the thermal relief of cold work in the initial AISI-1010 cold rolled blank has no discernable effect both on the residual stresses and the springback