Phase transformations in a simulated hot stamping process of the boron bearing steel

Autor: Wolfgang Bleck, Malek Naderi, M. Nikravesh, G.H. Akbari
Rok vydání: 2015
Předmět:
Zdroj: Materials & Design, Vol 84, Iss, Pp 18-24 (2015)
ISSN: 0264-1275
DOI: 10.1016/j.matdes.2015.06.108
Popis: A hot stamping process was experimentally simulated by a hot deformation dilatometer to investigate phase transformations and final properties of 22MnB5 boronearing steel. For this purpose, the phase fraction in the microstructure of boron bearing steel with and without hot deformation was evaluated. The results showed that mechanical stabilization of austenite during the deformation process led to decreased amount of military phases while bainite and reconstructive transformations, especially ferrite were promoted. But, when there was no martensite in the final microstructure, the effect of deformation on ferrite formation was negligible. Also, due to deformation, total hardness was decreased in cooling rates of higher than 6 °C/s. But, on the contrary, in cooling rates of lower than 6 °C/s, remarkably reverse results were achieved. Finally, the CCT and DCCT diagrams of elaborated steel were constructed. Keywords: Boron bearing steel, Phase transformation, Hot stamping, Hot deformation, Dilatometer
Databáze: OpenAIRE