This study explores the relationship between processing parameters, microstructure, and toughness in direct hot stamping of boron-alloyed high-strength steel (22MnB5). Its goal is to clarify microstructural evolution mechanisms during austenitization, forming and die-quenching, and establish process- microstructure-property relationships for toughness control. Using a Gleeble simulator and lab-scale setup, parameters like austenitization temperature (850-950°C), holding time, forming temperature and cooling rate were varied. Microstructural characterization employed SEM, EBSD and XRD; mechanical tests included tensile and Charpy V-notch impact tests (room/sub-zero temperatures). Results show full martensite dominates the microstructure, with its substructure and retained austenite content sensitive to thermal history. Toughness has a non-linear inverse relationship with strength. Optimal toughness relies on grain refinement and minimizing embrittlement, with austenitization control critical. A process window is defined to enhance strength-toughness balance for automotive applications.

Zhizhi Tang. Microstructure Evolution and Toughness Control During Hot Stamping of High-Strength Steel. Academic Journal of Engineering and Technology Science (2026), Vol. 9, Issue 1: 53-58. https://doi.org/10.25236/AJETS.2026.090107.

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