球铁后盖铸件缩孔缺陷的消除措施

分析认为球铁后盖铸件热节部位产生缩孔的原因是：原工艺在热节部位设置冒口,使热节增大;而且由于冒口颈偏小,早于铸件热节凝固封闭,使铸件热节不可能通过冒口颈获得补缩。为此采取如下改进措施：1）使冒口远离铸件热节,避免热节增大;2）在热节处设置厚大冷铁,使热节提早凝固收缩,从而可以通过冒口颈获得补缩。改进工艺后,缩孔问题得到了解决。

Measures to Eliminate Shrinkage Cavity Defects of Nodular Iron Rear Cover Casting

The reason causing shrinkage defect in hot spot area of the nodular iron rear cover casting was considered by analysis as that setting riser at the hot spot area in the former casting method caused the hot spot enlarged,however,due to having too smaller section,the riser neck solidified earlier than the hot spot and led to that the hot spot couldn't be fed through the riser neck.Therefore,the following improvements were adopted: 1) moving the riser to a location apart from the hot spot by some distance in o...