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研究了分段冷却工艺(超快冷+空冷+层流冷却)条件下一种钒微合金化双相钢的微观组织及强化机制。结果表明,试验钢的显微组织由(80.5%~83.7%)超细晶多边形铁素体和(16.3%~19.5%)块状马氏体组成,且80%以上的铁素体晶粒尺寸在1.0~2.5μm之间,粒子直径为4~9 nm的V(C,N)弥散的分布于铁素体基体中并与高密度位错交互作用而钉扎位错。在细晶强化、析出强化、位错强化及第二相马氏体强化的综合作用下,试验钢的抗拉强度达到1000 MPa以上,且具有优异的综合性能:Rm≥1000 MPa,RP0.2≥530 MPa,δ≥23.5%,RP0.2/Rm≤0.54,n≥0.23。
The microstructure and strengthening mechanism of a vanadium micro-alloyed duplex steel under segmented cooling process (ultra-fast cooling + air cooling + laminar cooling) were studied. The results show that the microstructure of the test steel consists of (80.5% -83.7%) ultrafine-grained polygonal ferrite and (16.3% -19.5%) massive martensite, and more than 80% of the ferrite grain size Between 1.0 and 2.5 μm, V (C, N) particles with a diameter of 4 to 9 nm diffusely distribute in the ferrite matrix and interact with high-density dislocations to pin dislocations. Under the combined effect of fine-grain strengthening, precipitation strengthening, dislocation strengthening and martensite strengthening of the second phase, the tensile strength of the test steel reaches more than 1000 MPa and has excellent comprehensive properties: Rm≥1000 MPa, RP0.2 ≥530 MPa, δ≥23.5%, RP0.2 / Rm≤0.54, n≥0.23.