基于数值模拟的高硅钼球墨铸铁排气歧管基体组织及性能预测

Microstructure and Properties Prediction for High Silicon-Molybdenum Nodular Cast Iron Exhaust Manifold Based on ProCAST Numerical Simulation

高硅钼球墨铸铁排气歧管需要有稳定一致的本体金相组织和力学性能才能在使用过程中拥有高温稳定性。美国的ProCAST软件已经拥有了球墨铸铁组织中石墨球数及珠光体含量的分析功能,进而预测本体的力学性能。本文通过对高硅钼球墨铸铁排气歧管铸造工艺的流体场、温度场以及微观组织的耦合模拟运算,分析出排气歧管在铸态的基体组织,进而对力学性能进行预测。通过分析得出结论,采用适当的铸造工艺完全可以使高硅钼球墨铸铁排气歧管在铸态满足本体金相组织和本体力学性能的要求。

The exhaust manifold made of high silicon-molybdenum nodular cast iron needs stable and consistent metallographic structure and mechanical properties in order to have high temperature stability during use. ProCAST software has the analysis function for graphite nodule count and pearlite content in nodular cast iron structure, and prediction function for the mechanical properties of the castings. In this paper, the matrix structure of the exhaust manifold in the as-cast state is analyzed by coupling simulation of the fluid field, temperature field and microstructure of the high-silicon molybdenum ductile iron exhaust manifold during casting process, and then the mechanical properties are predicted. Through analysis, it is concluded that the exhaust manifold made of high silicon-molybdenum nodular cast iron can completely meet the requirements of metallographic structure and mechanical properties in the as-cast state by adopting appropriate casting process.