Microstructure and mechanical properties of cold-rolled Fe-8Mn-xAl-0.2C medium Mn steel

doi:10.13251/j.issn.0254-6051.2023.02.011

Abstract

Abstract: Microstructure and mechanical properties of Fe-8Mn-xAl-0.2C(x=0, 3) cold-rolled medium Mn steel were studied by means of field emission scanning electron microscope, electron backscatter diffraction technology, X-ray diffractometer and electronic universal testing machine. The results show that the addition of Al increases the austenitizing temperature significantly, and the equiaxed austenite and ferrite dual-phase structures are obtained after annealing at higher intercritical annealing temperature. The stability of austenite is improved, which affects the strain hardening behavior of the tested steel during deformation, and the ductility of the steel is improved. When the Fe-8Mn-0.2C cold-rolled tested steel is annealed at 625 ℃, a good combination of strength and ductility is obtained with ultimate tensile strength (UTS) of 1220 MPa, tensile elongation (TE) of 44%, and UTS×TE of 54 GPa·%. But for the Fe-8Mn-3Al-0.2C cold-rolled tested steel, the good combination of strength and ductility is obtained with ultimate tensile strength (UTS) of 970 MPa, tensile elongation (TE) of 58%, UTS×TE of 56 GPa·% when annealed at 710 ℃. Furthermore, the addition of Al widens the intercritical annealing temperature window to attain good mechanical properties.

Key words: medium Mn steel, Al content, intercritical annealing, austenite stability, TRIP effect

CLC Number:

TG142.1

Zhang Zhenwei, Jing Songyang, Zhang Jincheng, Zhao Wenzhu, Ding Hua. Microstructure and mechanical properties of cold-rolled Fe-8Mn-xAl-0.2C medium Mn steel[J]. Heat Treatment of Metals, 2023, 48(2): 67-73.

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