过流冷却体法中高铬铸铁初生相的细化研究
Study on Refinement of Primary Phase in High Cr Cast Iron by Inclined
田 琴1， 周荣锋2， 蒋业华2， 朱 涛1
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作者单位：(1.贵州大学 材料与冶金学院， 贵州 贵阳 550003； 2.昆明理工大学 材料科学与工程学院， 云南 昆明 650093)
中文关键字：过流冷却体法； 高铬铸铁； 初生奥氏体； 初生M7C3碳化物； 细化
英文关键字： inclined cooling method; high chromium cast iron; primary austenite; primary M7C3 carbide; refinement
中文摘要：采用过流冷却体法制备高铬铸铁半固态浆料，对初生相的细化过程进行研究。结果表明：过流冷却体改变了高铬铸铁熔体的温度场、成分场，且合金熔体间、熔体与过流冷却体间存在剪切应力，使初生相得到细化；树枝状奥氏体和长杆状M7C3碳化物的细化受熔体的温度、温度梯度和粘度影响较大；在凹槽半径较小或温度较高的过流冷却体中熔体温度较高，温度梯度较小，粘度较小，使奥氏体的细化以枝晶臂熔断为主；M7C3碳化物因[0001]方向生长速度较小及剪切作用而细化；在凹槽半径较大或温度较低的过流冷却体中温度较小，温度梯度较大，粘度较大，剪切应力较大，使奥氏体的细化以枝晶臂弯曲折断为主，碳化物以折断、分裂而细化。
英文摘要： The refining course of primary phase in semi-solid slurries of high Cr cast iron during inclined cooling was studied. The results show that the temperature field and composition field of the molten high Cr cast iron change by inclined cooling, and the shear stress exists in molten alloy and between the molten alloy and the inclined cooling body, which make primary phase refine. The refining of dendritic primary austenite and long rod shape-M7C3 primary carbide is greatly affected by temperature, temperature gradient and viscosity in the molten alloy. The temperature , temperature gradient and viscosity of the molten alloy is relatively high, comparatively small and relatively small, respectively, in the smaller flute radius of inclined cooling plate or higher preheating temperature of inclined cooling plate, the dendritic arms of primary austenite refine in the form of fusing, the size of primary M7C3 carbides is refined as a result of low growth speed of [0001] direction of primary M7C3 carbides and shearing action; the temperature gradient and viscosity of the molten alloy is comparatively large and relatively big in the bigger flute radius inclined cooling or lower preheating temperature inclined cooling, which make shear stress in molten alloy comparatively large, the refining of dendritic arms of primary austenite is mainly in the form of bending off, the refining of primary M7C3 carbides is in the form of broken and split.