This study presents the effects of a moving heat source (MHS) on a rotating hollow steel disc heated from its one side surface under stagnant ambient conditions. As the disc rotates around the z-axis with a constant angular speed Omega, the heat source moves along from one radial segment to the next radial segment in the radial direction on the processed surface at the end of each revolution of the disc. Three-dimensional (3D) numerical calculations are performed individually for a wide range of thermal conductivity lambda of steel and for different Omega s. In order to obtain the thermal stress per heat flux intensity q(0), it is assumed that the thermo-physical properties of the disc do not change with temperature. The maximum effective thermal stress ratio varies in the range of 22-134 degrees C depending on lambda and Omega. While the MHS passes from one radial segment to the next radial segment, it causes an additional steeping of the effective thermal stress. However, when the values of lambda and Omega are increased, the maximum effective thermal stress ratio can be reduced by a considerable amount.