ith the aim of investigating the evolution of the substructure, the rolling of a steel strip containing 0•13%C, 0•75%Mn, and 0•048%Nb (all wt-%) was interrupted and the partially rolled strip water quenched. Using X-ray diVraction spectra, subgrain size and dislocation density were determined for specimens taken before and after the rolling passes. Both these microstructural characteristics were related to the rolling temperature and the amount of NbC precipitation. T he distribution of precipitates was investigated via T EM. At lower rolling temperature, particles precipitated in rows in the austenite temperature range.MST /3964