We determine single-wall carbon nanotube (SWCNT) thermal conductivity and tunable flattening dynamics at heat flux ranging from subject to different thermal loading of , using a nonequilibrium molecular dynamics (MD) simulation with true carbon potentials. The numerical model adopts Morse bending, a harmonic cosine, and a torsion potential. The applied Nosé-Hoover thermostate describes atomic interactions taking place between the atoms. Hot and cold temperature reservoirs are respectively imposed on both computational domain sides to establish the temperature gradient along the carbon nanotube. Atoms at the interface exhibit transient behavior and undergo an exponential type decay with exerted temperature gradient. The thermal impact causes system fluctuation in the initial leading to a transport region temperature as high as . The thermal relaxation process reduces impact energy influence after and leads to Maxwell’s distribution. Steady-state constant heat flux is observed after thermal equilibrium. Furthermore, the temperature curves show distinct high disturbance at initial time and linear distribution along the tube axial direction after steady state. Results suggest that thermal conductivity value increases with increasing CNTs subjected to thermal loading up to a temperature gradient of at least , representing thermal gradient convergence at heat conduction value . Simulation results yield precise understanding of nanoscale transient heat transfer characteristics in a single-wall carbon nanotube. Last, it is shown that given a thermal loading of sufficient intensity, the initial round cross section of the hot end of the nanotube transits through a series of triangular-like states to a flattened, rectangular configuration. As time elapses, the cross section oscillates between two fully perpendicular flattened states at a frequency that increases linearly with the intensity of the applied thermal load. The diameter of the passing pore within the flattened SWCNT is smaller than that of the original cross section but is independent of the intensity of the thermal load. The simulation results suggest that the structural deformation of the SWCNT induced by the application of a thermal load can be exploited to realize nanoscale mechanical systems/motors such as nano-clamps, for example, or active fluid transport devices for molecular selection or thermal pumping nano-vibrator applications.