Effect of Heating Rate during Continuous Annealing on Microstructure and Mechanical Properties of High-Strength Dual-Phase Steel

Journal Article · Thu Aug 15 04:00:00 EDT 2019 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-019-04253-2· OSTI ID:22970535

Di, Hongshuang ^[1]; Misra, R. D. K. ^[2]

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1. Northeastern University, State Key Laboratory of Rolling and Automation (China)
2. University of Texas at El Paso, Department of Metallurgical, Materials and Biomedical Engineering and Center for Structural and Functional Materials Research and Innovation (United States)

The study concerns the influence of heating rate during continuous annealing on microstructure and mechanical properties of high-strength ferrite–martensite dual-phase (DP) steel. The study suggests that the superheat (ΔT), carbon diffusion and distribution were strongly influenced by increasing the heating rate, leading to different microstructure and mechanical properties of DP steel. The morphology of martensite was observed to shift from network along ferrite grain boundaries to banded structure to uniformly dispersed, and the average ferrite grain size was refined from 5.3 to 2.0 µm. When the heating rate was 300 °C/s, the steel exhibited excellent mechanical properties with tensile strength (UTS) of 982 MPa, total elongation (TEL) of 17.5%, strength–elongation balance (UTS × TEL) of 17.2 GPa%, because of finer microstructure, uniform martensite distribution and low carbon content of martensite. Moreover, the precipitation strengthening effect of NbC is an important reason for the high-strength DP steels. In addition, the variation in strain-hardening behavior and fracture mechanism of steel subjected to different heating rates is discussed in relation to the microstructure.

• OSTI ID: 22970535
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 8 Vol. 28; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
FRACTURE PROPERTIES
GRAIN BOUNDARIES
GRAIN SIZE
HEATING RATE
MARTENSITE
NIOBIUM CARBIDES
STEELS
STRAIN HARDENING
TENSILE PROPERTIES