Reversed austenite for enhancing ductility of martensitic stainless steel

19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium

Dieck, S.^1 ; Rosemann, P.^1,2 ; Kromm, A.^2 ; Halle, T.^1

Institute of Materials and Joining Technology, Otto-von-Guericke University, Universitätsplatz 2, Magdeburg

39106, Germany^1

BAM - Federal Institute for Materials Research and Testing, Unter den Eichen 87, Berlin

12205, Germany^2

关键词: Annealing treatments;    Electron back scatter diffraction;    Martensite transformations;    Mechanical behaviour;    Microstructural changes;    Quenching and partitioning;    Retained austenite;    Reversed austenites;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/181/1/012034/pdf
DOI  :  10.1088/1757-899X/181/1/012034

来源: IOP

【 摘 要 】

The novel heat treatment concept, "quenching and partitioning" (Q&P) has been developed for high strength steels with enhanced formability. This heat treatment involves quenching of austenite to a temperature between martensite start and finish, to receive a several amount of retained austenite. During the subsequent annealing treatment, the so called partitioning, the retained austenite is stabilized due to carbon diffusion, which results in enhanced formability and strength regarding strain induced austenite to martensite transformation. In this study a Q&P heat treatment was applied to a Fe-0.45C-0.65Mn-0.34Si-13.95Cr stainless martensite. Thereby the initial quench end temperature and the partitioning time were varied to characterize their influence on microstructural evolution. The microstructural changes were analysed by dilatometer measurements, X-ray diffraction and scanning electron microscopy, including electron back-scatter diffraction. Compression testing was made to examine the mechanical behaviour. It was found that an increasing partitioning time up to 30 min leads to an enhanced formability without loss in strength due to a higher amount of stabilized retained and reversed austenite as well as precipitation hardening.