流变铸造半固态亚共晶高铬铸铁组织形成研究

Microstructural Evolution of Hypoeutectic High Cr Cast Iron in Rheoforming Casting

采用倾斜板冷却体法制备了亚共晶高铬铸铁半固态浆料 ,研究了亚共晶高铬铸铁半固态球状晶的形成条件及规律。结果表明 :通过控制合适的浇注温度 ,并对充型前的金属液进行激冷处理 ,同时对过冷的金属液施加适当的振动 ,可以获得球形或近球形的先共晶奥氏体非枝晶组织 ;在带有倾斜板冷却体的低温浇注情况下金属液的冲刷、流动及振动使熔体获得了均匀的溶质场和温度场 ,抑制了发达的先共晶奥氏体枝晶的形成 ,为获得球状晶提供了条件。

Semi-solid slurry of hypoeutectic high Cr cast iron was prepared by inclined cooling plate method. The condition and rule of semi-solid globular crystal formation of the cast iron were studied. The results showed that the spheroidal or near-spheroidal, non-dendrite primary austernite can be obtained sucessfully by regulating proper pouring temperature, melt chilling pre-treatment before mold filling and pertiment vibration of undercooled melt. Homogeneous solute and temperature fields resulting from impaction, flow and vibration of liquid metal during low pouring temperature,restricted the formation of developing primary austernite dendrite, which provided a basis to obtain spheroidal grain.