大型不锈钢导流壳的铸造工艺研究及实践

Casting Method Study and Practice for Heavy Stainless Steel Diversion Shell

大型不锈钢导流壳铸件结构复杂,易产生变形、裂纹和夹渣等缺陷。通过对产品结构、质量要求、材料及使用状况进行分析,提出了缺陷解决方案。结果表明,模具精度、组芯精度和合箱过程控制是保证大型导流壳尺寸精度的关键,能够生产出合格产品;在大尺寸薄壁结构部位增加冒口有防止缩松和均匀应力作用;环形肋有利于防止环形结构变形。

The heavy stainless steel discharge bowl for seawater circulation system,used in conventional island of nuclear power plant,is easy to generate some defects,such as distortion,crack,slag inclusion and so on when make the casting.In this paper,based on the analysis of the product shape,quality requirement,material and working environment,corresponding solutions were proposed,finally,the qualified pilot casting was made.The results show that,firstly,mold precision,core assembly precision and control of sand boxes closing are the key points to guarantee the dimensional precision of discharge bowl;secondly,the risers should be placed at the thin wall position to prevent shrinkage porosity and make the stress even;thirdly,circular ribs avail distortion avoidance.