In this paper a new X-ray method is proposed to evaluate the stress profile induced by different manufacturing processes. This method is based on the optimization of the whole experimental data by a non-linear least squares method. The unknown stress profile is defined by a mathematical function which is selected to satisfy all mechanical requirements (boundary conditions for forces and displacements, stress equilibrium and strain compatibility). The procedure is applied to shot peening of steel springs and to elastic-plastic bending of steel wires.