Comparison of Microstructure and Mechanical Properties of Deep Drawing Steel Sheet Prepared by Different Metallurgy Processes

The effects of two metallurgy processes with Ruhrstahl/Heraeus(RH)-Ladle furnace(LF) duplex calcium treatment and RH without calcium treatment on microstructure,mechanical properties and inclusion of deep draving quality(DDQ) level cold-rolled sheets were studied by means of OM,SEM and TEM.The results show that the tensile strength and yield strength of the cold-rolled annealed sheet with RH-LF duplex calcium treatment were lower than those with RH without calcium treatment,but the elongation was higher than the later.The plastic strain ratio value of r was influenced by the carburization phenomenon caused during the process of RH-LF duplex calcium treatment.And the quantity of inclusions in the steel dealed with RH-LF duplex calcium treatment was less and the inclusion size was smaller.