球墨铸铁Dg75阀体消失模近净型铸造

介绍消失模工艺生产Dg75闸阀阀体铸件的铸造工艺，生产过程中铸件重要装配尺寸精度的保证，铸件表面粗糙度、铸件表面碳夹杂缺陷及表面皱皮现象控制等试验情况。通过模具结构设计、成型工艺及参数的调整、浇注工艺的调整、陶瓷成型浇道的应用等措施，使铸件表面质量及尺寸精度符合客户验收标准。同时使铸件表面因轻微缺陷的返修率由试验初期的90％下降到10％以内，产品合格率达到99％。

Dg75 Ductile Cast Iron Valve in Lost Foam Casting

Dg75 valve case free machining in lost foam casting was introduced.The precision guarantee of important assemble dimension,control of castings surface cleanness,carbon defects in the castings and surface ripple were described also.The surface quality and dimension precision can meet requirements by the improving the mould structure and process,adjusting the parameters and pouring methods and applying ceramic gating system.The repairing rate resulting from slight defects in surface is decreased to low than 10% from 90%,and finished product rate reaches up to 99%.