Models for flow stress and dynamic recrystallisation of 316 stainless steel during hot forging

In the current work the flow stress characteristics of 316 stainless steel were determined by conducting hot compression tests using a Thermecmaster machine. Temperatures between 1223K-1423K at strain rates of 0.05,0.5 and 5 s(-1) were selected as these are typical of those occurring in hot forging operations. Much of the existing material data for stainless steel has been obtained at much higher strain rates for the modelling of rolling process. Based on the observed phenomena a constitutive model was set up as a function of strain, strain rate and temperature. As observed in previous studies, dynamic recrystallisation was found to be the major softening mechanism. An image analysis method was used to determine the mean grain diameters and calculate the recrystallisation fraction during the hot metal forming process.