Processing of Ultrafine-Grained Steels by Warm Rolling and Annealing

Journal Article · Fri Feb 15 00:00:00 EST 2019 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-018-3846-0· OSTI ID:22970959

Bhattacharya, Ankita ^[1]; Karmakar, Anish ^[2]; Karani, Arnab ^[3]; Ghosh, Mainak ^[4]; Chakrabarti, Debalay ^[1]

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1. Indian Institute of Technology, I.I.T. Kharagpur, Department of Metallurgical and Materials Engineering (India)
2. National Institute of Technology, N.I.T., Warangal, Department of Metallurgical and Materials Engineering (India)
3. TATA Steel, Materials Characterization Group, Research and Development (India)
4. CSIR-NML, Council of Scientific and Industrial Research, National Metallurgical Laboratory (India)

Low-carbon microalloyed steel was subjected to warm rolling followed by rapid transformation annealing (RTA) at 800-850 °C and subcritical annealing (SCA) at 600 °C to develop ultrafine ferrite grain structures (UFFG) with grain size less than 3 μm. The present study investigated the influence of light (40%) and heavy (80%) warm rolling deformation (LWR and HWR) applied during the finishing pass of two-pass rolling schedules on the microstructural evolution after rolling and subsequent annealing treatments. RTA treatment of HWR sample at a lower intercritical temperature for an optimum duration (800 °C, 30 s) developed UFFG-martensite dual-phase structure that offered the best combination of strength (YS ~ 900 MPa and UTS ~ 1200 MPa) and ductility (25% elongation). The SCA treatment provided sufficient time to achieve a uniform distribution of carbide particles throughout the ferrite matrix. SCA treatment of HWR at 600 °C for 4 h developed UFFG-carbide structure achieving YS of 800 MPa with 20% ductility. The SCA of LWR resulted in coarser ferrite grain structures (grain size > 5 μm) having higher ductility (more than 30%) but lower strength (UTS of 400-550 MPa) as compared to RTA.

• OSTI ID: 22970959
• Journal Information: Journal of Materials Engineering and Performance, Vol. 28, Issue 2; Conference: 2017 Materials Science and Technology Conference, Pittsburgh, PA (United States), 8-12 Oct 2017; Other Information: Copyright (c) 2019 ASM International; Country of input: International Atomic Energy Agency (IAEA); ISSN 1059-9495
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CRYSTAL LATTICES
DUCTILITY
ELONGATION
FERRITES
GRAIN SIZE
LOW ALLOY STEELS
MARTENSITE
ROLLING