This work is part of a wider study concerning Q&P steels subjected to different thermal cycles. The Q&Pprocesses were carried out on the Gleeble 3800 thermomechanical simulator. The steels investigated areidentified as Si, Al and Mo steels. The first results, presented in this article, are relative to a silicon steel afterquenching from different temperatures (always in the ?+? intercritical field), followed by partitioning atdifferent temperatures and for different times. The aim of these treatments was to evaluate the influence ofprocess parameters on the microstructure and consequently on the mechanical properties.The microstructure was investigated by optical and scanning electron microscopy (SEM); the phases wereidentified by electron back scattered diffraction (EBSD); the volume fraction of retained austenite, at roomtemperature, was measured by X-ray diffraction; and HV hardness measurements were performed.Transmission electron microscopy (TEM) examinations are in progress. Some mechanical properties weremeasured by tensile tests. The mainly phases present in the microstructure of the steel were: ferrite, lathmartensite and “retained” austenite. Their morphology and relative amounts depend on the thermal cycle. Inparticular, the treatments seemed to influence especially the austenitic areas undergoing transformation andtheir rate of transformation, the sizes and the more or less acicular morphology of structural elements. Insome samples, the presence of tempered martensite and / or bainite was found too.