石油机械压环铸件的壳型精密成形工艺

Shell Precision Forming Technology of Petroleum Machinery Clamp Ring Castings

介绍了压环铸件的结构及技术要求,阐述了采用静压造型工艺生产的铸件在环状厚大部位中心处存在严重的缩孔缩松问题,根据生产经验,改用壳型精密成形工艺:采用高密度EPS白模,涂覆面背多层无机浆料,层间撒砂,经烘干焙烧,制成强度高、透气性好、内壁洁净、外形完整的型壳,在负压状态下垂直浇注。经生产验证,该工艺提高了铁液充型、凝固及补缩能力,得到内部组织致密、外观光洁的压环铸件,避免了缩孔、缩松、渣孔、气孔缺陷,提高了铸件表面光洁度,成品率高,综合效应显著。

The structure and technical requirements of clamp ring were introduced.The problem of serious shrinkage and porosity problems in the center of the ring-shaped thick part produced by static pressure molding process was elaborated.Based on production experience,shell precision forming was used instead:use high-density EPS white mold coated with multiple layers of inorganic slurry,sanding between layers.After drying and roasting,a molded shell with high strength,good air permeability,clean inner wall and good appearance was made,which was poured vertically under negative pressure.After production verification,this process had improved the filling,solidification and feeding capabilities of molten iron,resulting in a clamp ring casting with dense internal structure and smooth appearance.It avoided defects such as shrinkage cavities,porosity,slag holes and pores and improved the surface finish.It had high yield and significant comprehensive effect.