Effect of Heat Treatment on Microstructure and Mechanical Properties of 800MPa Grade Ultra Low Carbon Bainite Steel

Abstract:

A new kind of bainite steel with ultra-low carbon content and Nb, Ti alloys has been developed. By applying thermomechanical control process, water quenching and tempering at different temperature, excellent properties have been obtained when tempered at 450°C, with the yield strength of 813MPa and elongation of 16.2%. The morphology observed by SEM shows that the microstructure consists of fine lath-shaped bainite, polygonal ferrite, quasi-polygonal ferrite and a small fraction of residual austenite or martensite-austenite constituents. In a TEM study plenty of precipitates with the size about 5-10nm were observed interacting with the dislocations, which is very significant for the optimization of strength and ductility.

• Periodical: Advanced Materials Research (Volumes 415-417)
• Pages: 943-946
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.415-417.943
• Online since: December 2011
• Authors: Zhan Lei Wei, Long Fei Zuo, Ben Ma, Li Xian Zhang, Hong Zhang, Zi Dong Wang
• Keywords: 800MPa, Ferrite, Heat Treatment, Low Carbon Bainite, Nanometer-Sized Precipitates

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