Effect of Friction Coefficient and Feed Rates on Residual Stresses of Zr-4 Processed by Swaging

Zirconium alloy has been extensively used as a cladding material in nuclear power reactors due to its low neutron absorption cross section, excellent tensile properties, fracture strength, and corrosion resistance. The influence of swaging parameters, feed rate (1.25 and 2 m/min), die angle (2–12°), friction coefficient (0.15, 0.2, 0.25, 0.3), and deformation (0–40%) on residual stress induced in Zirconium alloys is investigated numerically and experimentally in the present work. The residual stress in cold worked materials affects significantly their microstructural characteristics, tensile, fracture, and impact properties. The experimental hole drilling method is used to determine the residual stresses on swaged zirconium alloy. A three-dimensional finite element model was implemented in FEA software deform 3D to determine the residual stress in swaged zirconium alloys at different die angles. The residual stress is found to be decreasing with the increasing friction coefficient at the center of the specimen but it increased at the surface of the specimen. The nature of residual stress is compressive at the surface and tensile at the center for all friction coefficients at both feed rates. The optimum swaging parameters (die angle, feed rate, and friction coefficient) were proposed for improving production, achieving better mechanical properties, and lowering residual stresses.