Microstructure, properties and surface quality of Q550D V-N-microalloyed steel extra heavy plate

doi:10.13251/j.issn.0254-6051.2021.04.011

Abstract

Abstract: Effect of controlled rolling and controlled cooling process on microstructure and properties of 50 mm thick V-N-microalloyed steel plate produced in industrial trial production was studied by means of OM, SEM,TEM and tensile tester. The results show that the microstructure of the steel is composed of acicular ferrite, polygonal ferrite and a small amount of granular bainite when the final cooling temperature is 630 ℃, and V(C, N) precipitated particles are observed. The yield strength of the middle part of the steel is 599 MPa, elongation is 20%, and -20 ℃ impact absorbed energy is 199 J. The results show that the surface quality of the plate is improved obviously by decreasing the content of Al in the steel.

Key words: V-N-microalloyed steel, medium plate, V(C,N) precipitation, surface quality

CLC Number:

TG339

Ma Heng, Huo Xiaoxin, Wu Hongyan, Gao Xiuhua, Du Linxiu. Microstructure, properties and surface quality of Q550D V-N-microalloyed steel extra heavy plate[J]. Heat Treatment of Metals, 2021, 46(4): 65-69.

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