烧结机栏板消失模铸造数值模拟及组织性能研究

Numerical Simulation and Microstructure as well as Mechanical Properties of the Lost Foam Casting Sideboard

运用View Cast模拟软件对烧结机栏板消失模铸造过程进行数值模拟,预测铸件可能产生缩孔、缩松的位置和大小。结果表明,铸件实现了顺序凝固,没有产生缩孔、缩松等缺陷,铸件组织致密。铸态组织主要以铁素体、珠光体以及球状石墨为主,加热至500、700℃时组织和硬度没有发生明显变化;当加热至900℃时发生相变,产生破碎状铁素体和网状铁素体,硬度显著增大。氧化试验分析发现,不同温度下试样表面生成结构和成分均不同的氧化膜,影响铁和氧的扩散速率,使试样的氧化速率有较大的差异。

The software View Cast was employed to predict the sizes and positions of the shrinkage porosities（holes）in the sideboard produced by lost foam casting.The results reveal that the sequential solidification can be achieved in the casting process,so absence of defect such as shrinkage porosities can be observed in the sideboard with sound structure,meeting the technical requirements.The microstructure of the sideboard prepared is mainly composed of acicular ferrite and pearlite as well as shperoidal graphite.With heated to 500 ℃and 700 ℃,there exist no obvious changes of the hardness and microstructure.With heated to 900℃,ferrite austenite is transformed into the broken ferrite and pearlite uniformly distributed in the microstrucutre after cooling,at the same time,the samples are increase in hardness.The analysis of oxidation experiments show that the temperatures have great influence on the oxidation rate of sample,which are attributed to different thickness of oxide films formed under different temperatures resulting in the varied oxidation rate of the samples due to changing the diffusion rate of Fe and oxygen.