Residual Stresses in Cold-drawn Pearlite Rods by High Energy Synchrotron Radiation and Thermal Neutron Diffraction

Residual stresses in a cold drawn pearlitic rod of 18 mm in diameter have been studied by synchrotron radiation and neutron diffraction. The aim has been to characterise the complete residual stresses, including the total phase stresses, macrostresses and microstresses, due to cold drawing. Both techniques have revealed characteristic residual stress profiles along the radius of the rod for the ferrite phase, while the synchrotron radiation measurement has also produced residual stress profiles for the minor cementite phase (11% in weight). Good agreement between the two techniques has been observed. Residual macrostresses derived from the synchrotron measurement show a large variation from center to surface of the rod. The phase stresses for ferrite are dominated by the macrostresses. On the other hand, residual microstresses change less significantly along the radius of the rod and they prevail in the cementite phase.