Title

Mechanical Properties and their Dependence on Microstructure in Hot-Rolled 3rd Generation Advanced High Strength Steels

Abstract

Third generation advance high strength steels with microstructures of acicular ferrite and retained austenite were investigated and meet mechanical property goals. A good combination of strength and ductility were achieved with duplex ferrite and austenite microstructures where cementite formation was suppressed. Transformation induced plasticity (TRIP) behavior produced rapid work hardening. The mechanical properties of two hot-rolled steels with duplex microstructures were compared and had the following compositions: (1) Fe-0.14C-13.87Mn-1.42Si-3.51Al; and (2) Fe-0.06C-14.2Mn-1.85Si-2.38Al. These steels were cast, homogenized, and hot rolled at 900°C to obtain a refined microstructure with ultimate tensile strengths and elongations to failure of 865 MPa and 39% and 1,217 MPa and 28%, respectively. The amount of metastable austenite in both compositions decreased after tensile testing from 58% and 28% to 6% and 0%, respectively. Microstructures were characterized using optical microscopy, scanning electron microscopy (SEM), and x-ray diffraction.

Meeting Name

TMS Annual Meeting and Exhibition (2010: Feb. 14-18, Seattle, WA)

Department(s)

Materials Science and Engineering

Keywords and Phrases

3rd generation ahss; Acicular ferrite; FeMnAl; Advanced high strength steel; Austenite microstructure; Duplex microstructures; Hot rolled steels; Metastable austenite; Refined microstructure; Retained austenite; SEM; Third generation; Transformation induced plasticity; Ultimate tensile strength; Work hardening

International Standard Book Number (ISBN)

9781617822933

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2010 Minerals, Metals and Materials Society (TMS), All rights reserved.

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