Evaluation of 22MnB5 Steel Austenitization Sub-Models for Simulating the Heating Phase of Hot Stamping

Abstract

Abstract The heating phase of hot stamping is the most time-and energy-intensive part of the process, and therefore offers significant potential to improve process efficiency. This requires a robust thermometallurgical model that predicts the blank heating profile and the austenitization progress inside a roller hearth furnace. In this paper, an IM austenitization model for 22MnB5 steel is derived using dilatometry data and evaluated against a JMAK type model using temperature profiles of coupons heated within a laboratory-scale muffle furnace and blanks heated within a roller hearth furnace. The austenitization rates predicted by the two models are then compared to the inferred austenitization processes from those temperature profiles. The result shows that the IM model has potential to capture the trend of austenitization process, especially the rapid pearlite dissolution at the beginning of the transformation, whereas the JMAK type model is too restrictive and fails in this regard.