减少QT400-15飞轮壳缩孔、缩松的措施

摘要

The shrinkage defect situation of QT400-15 grade nodular iron flywheel housing produced with former casting method was introduced.It was considered by analysis that the main reason causing shrinkage defects was that the areas with thick wall and isolated hot spots were lacking in feeding and the mold rigidity was not enough high.The shrinkage defects in above mentioned areas have been basically eliminated by adopting following measures:setting chills in the mold and cores,setting additional feeders,increasing mold rigidity,properly controlling composition of the iron melt and pouring temperature.As the result,the total rejection rate of the casting has been reduced to about 6％.%介绍了QT400-15飞轮壳铸件原生产工艺所产生的缩孔、缩松情况.分析认为缩孔、缩松的主要原因是:铸件厚壁处及孤立热节处得不到补缩,以及铸型紧实度偏低.通过在外砂型和砂芯上加冷铁、增加补缩冒口、提高铸型紧实度、合理控制铁液化学成分和浇注温度等措施,使该部位的缩孔、缩松基本消除,从而使铸件的综合废品率降至6％左右.