船用柴油机活塞铸造顺序凝固工艺设计及数值模拟

Sequential Solidification Design and Numerical Simulation of Casting Process for Marine Diesel Piston

在生产壁厚变化较大的复杂球墨铸铁零件中,仅依靠球墨膨胀难以消除铸件缩孔、缩松等缺陷。通过数值模拟,分析了某船用柴油机活塞铸造缩孔、缩松产生的成因。采用阶梯流道、冷铁及冒口布置建立了顺序凝固方案,并通过数值模拟及试验方法进行验证。结果证明,通过顺序凝固方案能够消除活塞缩孔、缩松缺陷。

The shrinkage porosity in ductile iron components was not be completely eliminated by graphitizing expansion as a result of the large variation in the thickness of the component and its complexity in structure.Origination of shrinkage porosity in a marine diesel piston was visualized by numerical simulation.The sequential solidification design was established by adopting the step runner,arranging chill and riser,which was verified by numerical simulation and practical experiment.The results indicate that the shrinkage porosity(hole)in the piston can be effectively eliminated by employing sequential solidification design.