Low Carbon Steel Sheets Obtained by Reactive Annealing

This paper deals with the possibility of reducing carbon content by heat treatment in reactive atmospheres in order to improve plastic deformations properties of steel sheets. The heat treatment involves a decarburation annealing after a cold rolling, as opposed to the traditional process that performs the heat treatment in non-reactive atmospheres. Some of the most relevant variables were studied. For this, commercial hot rolling steel sheets were cold rolled with different grades of cold reduction (60%, 70% and 80%). The recrystallization temperature and the decarburation kinetics were determined by heat treatments performed at temperatures varying between 600 and 700oC, for variable lengths of time up to 2 hours. The grain size evolution was monitored by metallography. In order to analyse the plastic properties of the treated sheets, the n and r coefficients were obtained by tension tests and the sheet texture was determined by X-ray diffraction.