Sh ess analysis in a duplex steel -: X-ray diffraction methodologies of macro and pseudo-macro stress analysis in a textured duplex stainless steel

Stress distribution in each phase of a highly textured duplex stainless steel is analysed after plastic prestrain and also during an in situ elastic bending solicitation. 2 X-ray diffraction methods were used to take into account the crystallographic texture in the stress analysis. In the classical sin(2)psi method, anisotropic X-ray elastic constants were used. Although the stress uncertainty is satisfying, epsilon(phi psi) versus sin(2)psi curves could not be fully described. This is due to low diffracting intensity directions and the presence of local plastic strain incompatibilities. The crystallite group method, which was the 2nd approach used, leads to the smallest obtained uncertainties. This method only gives the stress corresponding to the major volume fraction of the considered phase. X-ray analysis indicates that the elastic behaviour can be considered the same for the 2 phases as observed during elastic bending. In the case of plastic prestrain, the determined residual stresses indicate a lower elastic limit of the ferritic phase, due to the higher nitrogen content of the austenitic phase.