Microstructural Evolution of Ultrafine Ferrite During Plate Steel Processing Using Intermediate Cooling

摘要

A 0.12 wt.% C - 1.26 wt.% Mn steel was studied to evaluate phase transformations that occurred during a specific thermal processing method designed to simulate steel plate surface layer microstructural evolution during processing with intermediate cooling. All process simulations used a Gleeble thermomechanical simulator along with thermal practices developed previously. After intermediate cooling was completed during processing, slight reheating of the plate surface layer region would occur due to heat retained in the plate core. Microstructural evaluation of Gleeble samples quenched at several points along the thermal profile allowed interpretation of microstructural evolution during processing. The microstructure that was present at the point where deformation would be applied consisted of approximately 75% ferrite, 25% austenite and some small, undissolved cementite particles.