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通过连续退火实验,研究了贝氏体区等温处理对钒微合金化TRIP钢组织性能的影响。等温≤60 s时,组织由铁素体、分布不均匀且成堆聚集的残留奥氏体及贝氏体/马氏体组成。等温120～180 s后,组织中马氏体减小,残奥含量趋于稳定且分布弥散、均匀,基体上存在钒的析出。EBSD分析结果表明等温时间达到120 s后,大、小角度晶界的分布趋于稳定,以大角度晶界为主。所有等温时间范围内,铁素体晶粒尺寸大体呈正态分布,其中2～3μm的铁素体晶粒占很大比例。等温时间较短时,连续退火钢板呈现出高抗拉强度(1100 MPa)、低屈服强度(495 MPa)和低伸长率(20.3%)的特性。随着等温时间的延长,呈现出相对低抗拉强度(885 MPa)、高屈服强度(570 MPa)和高伸长率(27.8%)的特性,而且加工硬化指数(0.29)、各向异性指数(1.04)和强塑积(24603 MPa.%)也较为优良。
Through continuous annealing experiment, the effect of bainite zone isothermal treatment on the microstructure and properties of vanadium microalloying TRIP steel was studied. Isothermal ≤ 60 s, the organization from ferrite, uneven distribution and accumulation of residual austenite and bainite / martensite composition. After isothermal 120 ~ 180 s, the martensite in the tissue decreased, the content of Paralympic tend to be stable and distributed dispersedly, and the precipitation of vanadium existed on the matrix. The results of EBSD analysis show that the distribution of large and small angle grain boundaries tends to be stable after the isothermal time reaches 120 s, mainly at the large-angle grain boundaries. In all the isothermal time range, ferrite grain size is generally normal distribution, of which 2 ~ 3μm ferrite grains accounted for a large proportion. Continuous is annealed steel shows the characteristics of high tensile strength (1100 MPa), low yield strength (495 MPa) and low elongation (20.3%) when the isothermal time is short. With the extension of isothermal time, the properties of relatively low tensile strength (885 MPa), high yield strength (570 MPa) and high elongation (27.8%) were obtained, and the work hardening index (0.29), anisotropy index (1.04) and strong plastic product (24603 MPa.%) Are also superior.