摘要：Num.rical s.m.lation technology was.applied for optim.zing the cas.ing des.gn and conditions.in large cas. iron cas.ings.for m.rine engine. By the s.m.lation of m.ld filling and s.lidification s.quences.the problem.0}of the previous.cas.ing conditions.were analyzed and m.rked im.rovem.nts.for large cylinder liner parts.were derived from.thes. res.lts. Es.ecially the am.unt and pos.tions.of chills.were optim.zed to increas. the m.chanical properties.and to m.nim.ze the s.rinkage and m.croporos.ty in the cas.ings. Ultras.nic tes.ing, penetration tes.ing and m.chanical property tes.ing were carried out for the parts.with the m.dified cas.ing conditions. It s.owed that no defects.in the cas.ings.were found and the productivity could be dis.inctly increas.d. The m.chanical properties.s.tis.ied als. the s.ecification dem.nded.