ON THE HOT WORKABILITY OF LOW-CARBON Mn-Nb STEEL

The hot torsion tests on low-carbon Mn-Nb steel were carried out of the es-tablishment of the constitutive equation of the power function and of the deter-mination of the relationship between flow stress of a steady state and hot ductility.An approach to the process of dynamic recrystallization was also made after con-sideration in the effect of strain accumulation.The influences of temperature,strain rate,Nb(CN)precipitation on the dynamic fractional softening have beenanalyzed.During dynamic recrystallization,the variation of activation energy orstress exponent reflects the precipitation of Nb(CN)to a certain extent.The effectof temperature and strain rate on the Nb(CN)precipitation may be quantitativelyillustrated by(?) which is defined as so-called precipitation exponent.Furthermore,the correlation among the strain rate sensitivity,temperature and shear strain hasalso been studied.