AbstractStatic strain aging in steel of approximately eutectoid composition has been investigated using tensile testing and transmission electron microscopy for material in both low prestrain and drawn conditions. Two dominant modes of strain aging have been identified: (a) a low temperature mechanism dependent on interstitial solute diffusion and (b) a pseudo recovery mechanism which operates above 150°C. In the low temperature range, there exists a microstructure dependent transition temperature below which the kinetics of aging obeys a t1/3relationship and above which a rate exponent of approximately 1/2 is obtained. This has been attributed to a change from planar solute diffusion to dissolution of cementite as the rate limiting process.MST/1067