摘要：Numerical simulation technology was applied for optimizing the casting design and co.ditions in large cast iron castings for marine engine. By the simulation of mold filling and solidification sequences the problems of the previous casting co.ditions were analyzed and marked improvements for large cylinder liner parts were derived from these results. Especially the amount and positions of chills were optimized to increase the mechanical properties and to minimize the shrinkage and microporosity in the castings. Ultrasonic testing, penetration testing and mechanical property testing were carried out for the parts with the modified casting co.ditions. It showed that no defects in the castings were found and the productivity co.ld be distinctly increased. The mechanical properties satisfied also the specification demanded.