高铬铸铁中不同初生相在不同凹槽半径过流冷却体中的形貌演变

Morphology Evolution of Different Primary Phase in High-chromium Iron at Different Groove Radius of Slope Plate Cooling Body

采用过流冷却体法制备高铬铸铁半固态浆料,研究高铬铸铁中不同初生相在不同凹槽半径过流冷却体中的形貌演变。结果表明:采用过流冷却体法细化高铬铸铁半固态浆料组织是行之有效的方法。呈树枝状长大的初生奥氏体的细化在凹槽半径较小的冷却体中以熔断为主,在凹槽半径较大的冷却体中以扭折为主。呈杆状长大的初生M7C3型碳化物在冷却体中的细化以破碎、折断、劈裂为主,在凹槽半径较小的冷却体中较凹槽半径较大的冷却体中易形成包裹层较厚的杆状碳化物,且较难被破碎和折断。

Semi-solid slurries of high-chromium iron were prepared with slope plate overflowing cooling method, and the morphology evolution of different primary phase in those slurries at different groove radius of slope plate cooling body was studied. The results show that the slope plate cooling method is an effective method to refine the microstructure of semi-solid slurry of high-chromium iron. The refinement of primary austenite by dendritic growth in a relatively smaller groove radius of cooling body is mainly in the form of fusing, and the structure of that in relatively larger groove radius of cooling body is mainly kinking. The refining of primary M7 C3 carbides hy rhabditiform growth is mainly in forms of cracking, hreaking and splitting. For primary M7C3 carbides, it is relatively easy to form thicker swathing layer long rod primary carbides in smaller groove radius of cooling body than in bigger groove radius, and these carbides are difficult to be crushed and broken.