不锈钢铸件冒口偏离热节的工艺设计

为防止铸钢件冒口根部的缩孔、缩松缺陷,运用冒口偏离热节动态顺序凝固工艺理论,用模数法设计1Cr18Ni9Ti不锈钢砂铸150FYL液下泵泵体和熔模精铸保温截止阀阀体补缩冒口,在补缩安全系数为1.14～1.20时能较好地消除铸件缩孔、缩松缺陷,获得结构致密的铸件。按技术要求作2～4 MPa,保压3 min水压试验,无一件出现渗漏。批量生产证实,所设计的工艺实用可靠,产品质量稳定,有较好的技术经济效果。

Technological Design of Riser Deviating from Hot Spot for Stainless Steel Castings

In order to prevent the formation of the shrinkage and dispersed shrinkage in the riser pad of steel casting,the dynamic directional solidification theory of riser deviating from hot spot and the moduli calculation method were used to design riser for the 150FYL 1Cr18Ni9Ti stainless steel body of submerged pump and body of heat insulating shut off valve,which are produced by sand molding and precision casting respectively.When feeding safety factor is 1.14~1.20,these defects such as shrinkage and dispersed shrinkage can be eliminated,and the compact casting can be obtained.Hydraulic tests show that no valves have leakage under 2~4 MPa holding for 3 min.It is verified from batch production that the technique designed is practical and reliable,and the quality of product is stable,thus it has good technical and economical effects.