Influence of intercritical annealing to obtain austenite in 3rd generation AHSS medium Mn steel Article uri icon

abstract

  • Intercritical annealing is the most relevant stage in obtaining 3rd generation Advanced High-Strength Steels (AHSS), therefore controlling the temperature, holding time, and cooling rate are essential since they influence the microstructure and mechanical properties. The present work evaluates the influence of temperature, holding time, and cooling rate on the austenite fraction and stabilization of a 10.7%25 Mn steel. The specimens were heat treated at 650 and 700 °C with 1.0, 1.5, and 2.0 h holding times and cooled in oil and air. The microstructure obtained is composed of austenite and ferrite, which becomes more homogeneous with increasing temperature and soaking time. Using X-ray diffraction (XRD), the phase changes in each condition were identified, showing that %25C of the austenite increased with increasing holding time. Austenite stabilization, which favors the presence of the Twinning Induced Plasticity (TWIP) and Transformation Induced Plasticity (TRIP) mechanisms, was achieved at 700 °C for 2 h.

publication date

  • 2025-01-01