In order to reduce the alloying cost, Mn-series low carbon water-quenched grain boundary allotriomorphic ferrite (FGBA)/granular bainite (BG) steels have been developed. The effect of 0.06 wt.% Nb on microstructure and mechanical properties of FGBA/BG steel was investigated. The result showed that the addition of 0.06 wt.% Nb improved the hardenability of the FGBA/BG steel, refined the grain size of FGBA, promoted the granular bainitic transformation, and refined the granular bainite including its bainitic ferrite and martensite/austenite (M/A) constituents. With the addition of 0.06 wt.% Nb, the yield strength increased from 560 to 741 MPa, and the impact energy increased from 93 to 151 J, respectively, for 30-mm thickness steel plates. It is supposed that the addition of 0.06 wt.% Nb could improve the mechanical properties of the FGBA/BG steel by refining the microstructure and increasing the amount of strengthening phases.
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机译：为了降低合金化成本，开发了Mn系列低碳水淬晶界同素异形铁素体（F GBA ）/粒状贝氏体（B G ）钢。研究了0.06wt。％的Nb对F GBA / B G 钢的组织和力学性能的影响。结果表明，添加0.06 wt。％的Nb可以改善F GBA / B G 钢的淬透性，细化F GBA的晶粒尺寸，促进了颗粒状贝氏体转变，并细化了包括其贝氏体铁素体和马氏体/奥氏体（M / A）成分的颗粒贝氏体。添加0.06 wt。％的Nb，对于30毫米厚的钢板，屈服强度从560 MPa增加到741 MPa，冲击能量从93 J增加到151J。据推测，添加0.06 wt。％的Nb可以通过细化组织和增加强化相的数量来改善F GBA / B G 钢的力学性能。 。
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