Li Bingjun, Li Jing, Liu Weijian, Zhang Ti. Research on Strengthening Mechanism of Microalloying Elements in Low-carbon Bainite Steels Produced with TMCP Process[J]. IRON STEEL VANADIUM TITANIUM, 2013, 34(3): 77-82. doi: 10.7513/j.issn.1004-7638.2013.03.016
Citation:
Li Bingjun, Li Jing, Liu Weijian, Zhang Ti. Research on Strengthening Mechanism of Microalloying Elements in Low-carbon Bainite Steels Produced with TMCP Process[J]. IRON STEEL VANADIUM TITANIUM, 2013, 34(3): 77-82. doi: 10.7513/j.issn.1004-7638.2013.03.016
Li Bingjun, Li Jing, Liu Weijian, Zhang Ti. Research on Strengthening Mechanism of Microalloying Elements in Low-carbon Bainite Steels Produced with TMCP Process[J]. IRON STEEL VANADIUM TITANIUM, 2013, 34(3): 77-82. doi: 10.7513/j.issn.1004-7638.2013.03.016
Citation:
Li Bingjun, Li Jing, Liu Weijian, Zhang Ti. Research on Strengthening Mechanism of Microalloying Elements in Low-carbon Bainite Steels Produced with TMCP Process[J]. IRON STEEL VANADIUM TITANIUM, 2013, 34(3): 77-82. doi: 10.7513/j.issn.1004-7638.2013.03.016
Microstructures and second phase precipitates in microalloyed high-strength steel Q690D produced with TMCP process are analyzed by means of optical microscope(OM),transmission electron microscopy(TEM),and energy dispersive spectroscopy(EDX) in order to study the strengthening mechanism.It is found that the surface microstructure is mainly consisted of lath bainite,a small amount of granular bainite and acicular ferrite,and the central microstructure of granular bainite and polygonal ferrite.Most of the second phase precipitates are niobium and titanium carbonitride with a size of about 20nm in length,dispersively distributing in the matrix in the shape of square or quasi-square.Boron,mainly existing in the form of acid-soluble boron,remarkably increases the hardenability of the steel.Results show the strengthening mechanism is dominated by bainite transformation strengthening,fine grain strengthening and precipitation strengthening.
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