Abstract—A method for solving the boundary value problem of a residual stress relaxation in a surface-hardened solid cylinder under creep conditions with initially defined and rigidly fixed axial deformation and torsion angle has been developed. It includes a phenomenological methodology for reconstructing the stress-strain state after hardening and its kinetics during relaxation of axial load and torsional moment due to creep. In order to illustrate the method, a cylindrical specimen made of ZhS6KP alloy after pneumo-shot peening is considered. A detailed investigation of the residual stress relaxation has been performed for various combinations of initially defined and fixed axial and angular deformations at temperature of 900°C. The results of a comparative analysis of obtained data with data for the residual stress relaxation under pure temperature loading in the absence of mechanical loads are presented.