Effect of niobium and phase transformation temperature on the microstructure and texture of a novel 0.40% C thermomechanically processed steel

Journal Article · Wed Aug 15 04:00:00 EDT 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.05.056· OSTI ID:22805093

Javaheri, Vahid ^[1]; Khodaie, Nasseh ^[2]; Kaijalainen, Antti; Porter, David ^[1]

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1. Materials and Production Engineering Unit, Faculty of Technology, University of Oulu (Finland)
2. Department of Chemical and Materials Engineering, University of Alberta (Canada)

Field emission scanning electron microscopy, electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) have been employed to investigate the effect of niobium and phase transformation temperature on the evolution of microstructure and texture in a novel thermomechanically processed, medium‑carbon, low-alloy steel intended for slurry pipeline applications. Thermomechanical processing consisted of hot-rolling in the austenitic region with deformation both above the recrystallization limit temperature and below the recrystallization stop temperature. Immediately after rolling, specimens were directly quenched in water to two different temperatures of 560 °C and 420 °C and subsequently furnace cooled from those temperatures to simulate the cooling of coiled strip on a hot strip mill. The microstructure of samples quenched to 560 °C mostly comprised of upper bainite, whereas the samples quenched to 420 °C mainly consisted of lath-type lower bainite. The transformation texture of all samples at the mid-thickness position consisted of α, γ and ε-fibers with high intensities close to the transformed copper, transformed brass and rotated cube components. The addition of 0.013 wt% Nb refined the microstructure and sharpened the texture. The texture of the small fraction of retained austenite present in the final microstructures indicated that the main bcc texture components result from the brass and copper components in the parent austenite.

• OSTI ID: 22805093
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 142; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
AUSTENITIC STEELS
BACKSCATTERING
BCC LATTICES
CARBON STEELS
DEFORMATION
ELECTRON DIFFRACTION
FIBERS
FIELD EMISSION
LOW ALLOY STEELS
MICROSTRUCTURE
PHASE TRANSFORMATIONS
RECRYSTALLIZATION
SCANNING ELECTRON MICROSCOPY
TEXTURE
X-RAY DIFFRACTION