Study on austenite reversion and its influence on the magnetic properties of a duplex stainless steel cryorolled at 77K

• Grant number: 23/05852-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2023
• End date: November 30, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Maria Jose Ramos Sandim
• Grantee: Rafael José Vieira Mesquita
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil
• Associated scholarship(s): 23/13092-2 - Advanced microstructural characterization of a lean duplex stainless steel cryorolled at 77K and isothermally annealed up to 800ºC, BE.EP.IC

Abstract

In this Scientific Initiation project, the austenitic reversion in a UNS S32304 lean duplex stainless steel rolled at 77 K will be investigated. Due to the combination of good mechanical properties and corrosion resistance, this steel is used in the chemical and petrochemical industries. This steel exhibits strain-induced martensite (SIM) formation. Recent works by our research group reported on SIM and austenite reversion for cold rolled UNS S32304 (room temperature). The main focus of this project is the study of the austenite reversion after cryorolling at 77 K up to 50% of thickness reduction and subsequent isothermal annealing at several temperatures up to 800oC (1 h). Due to the low deformation temperature, a significant increase in the volumetric fraction of SIM is expected. The microstructural characterization of the material will involve Vickers hardness tests, X-ray diffraction and optical (OM) and scanning electron (SEM) microscopies. Representative samples will be mapped via EBSD (electron backscatter diffraction) for phase quantification. Regarding the magnetic measurements, hysteresis loops will be obtained at room temperature, from which the magnetic parameters Ms and Hc will be obtained. The microstructural changes of the material will be compared to the evolution of these magnetic parameters. To the best of our knowledge, so far there are no works reported in the literature on the austenite reversion in a UNS S32304 lean duplex steel cryorolled at 77 K.