Abstract: The aging hardening behavior of low carbon bainitic steels with Cu, Nb, Cr, and Mo was determined, and creep tests for various steels were conducted on a Gleeble-1500 thermal simulator. Optical microscope and TEM were employed to study the microstructure and precipitates of the steels respectively. The results indicate that there is an obvious aging hardening behavior during the aging of copper containing steels; a plateau occurs on the creep curve at different temperatures, which results from the precipitation. The occurrence of the plateau means the start of the precipitation process, and when the precipitation finishes the plateau disappears.