Static softening behavior of 316L stainless steel under flexible rolling process

Flexible rolling is important for increasing rolling production capacity. Since the wear rolls withdrawn and new rolls launched into the rolling process causing thermal deformation parameters variation, such as deformation temperature, strain rate, and strain. This paper studies the coupling behavior of static recrystallization (SRX), metadynamic recrystallization (MDRX), and thermal deformation parameters based on the double-pass thermal simulation experiments, analyzes the flow stress curves and reveals the variation law of recrystallization with thermal deformation parameters. The result shows that the second-pass flow stress of SRX is significantly dependent on the inter-pass time, deformation temperature and strain rate, Compared to MDRX, SRX requires time to nucleus of conception and is more influenced by initial strain. Considering the recovery effect and the multi-pass static softening solution algorithm of materials, the kinetic models of SRX and MDRX are established, and the predicted values of the models are in good agreement with the experimental values. The EBSD microstructure characterization technique is used to characterize the morphology of SRX and MDRX. The result shows that increasing inter-pass time, deformation temperature and strain rate can promote the SRX and MDRX process and improve static softening effect. Under the condition of constant deformation temperature and strain rate, increasing the initial strain can increase the SRX volume fraction. However, deformation temperature and strain rate have a more significant effect on the static softening than the initial strain. This paper provides a theoretical basis for designing and optimizing recrystallization behavior of flexible rolling gaps.