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利用Formastor-FⅡ全自动相变仪模拟研究了一种Fe-0.24C-0.3Si-1.0Mn-0.56Cr-0.17Mo(质量分数,%)钢在冷却过程中的碳配分行为及其对马氏体和残余奥氏体的影响,用扫描电镜、透射电镜进行微观组织表征,用X射线衍射法和电子背散射衍射法测定残余奥氏体体积分数。结果表明,试验钢分别经末段慢冷和直接快冷工艺冷却后均获得马氏体+残余奥氏体两相组织,其中直接快冷工艺所得马氏体相对杂乱,尺寸较小,残余奥氏体体积分数较少;而末段慢冷工艺所得马氏体板条较长,且发生了碳的配分,残余奥氏体体积分数较多,以薄膜状分布在马氏体板条间,板条内部含有高密度位错。
Carbon fractionation behavior of Fe-0.24C-0.3Si-1.0Mn-0.56Cr-0.17Mo (mass fraction,%) steel during cooling was investigated by means of Formastor-F Ⅱ automatic phase change instrument. And retained austenite. The microstructure was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The volume fraction of retained austenite was determined by X-ray diffraction and electron backscatter diffraction. The results show that the martensitic and retained austenite microstructure of the test steel is obtained after both the slow cooling of the final stage and the cooling by the direct rapid cooling process. The martensite obtained by the direct rapid cooling process is relatively messy and the size is small. The residual austenite The volume fraction of martensite is less; while the martensite lath obtained in the slow cooling process of the last stage is longer, and the distribution of carbon occurs, the volume fraction of retained austenite is larger, and the martensite lamellae are distributed in the form of thin film, The slats contain high density dislocations inside.