双层排气管铸件缺陷产生原因及解决措施

Reasons Causing Defects of Double-Row Exhaust Pipe Casting and Solution Measures

分析了双层排气管法兰测温孔搭子部位缩孔及直管夹层部位气孔和冷隔缺陷产生的主要原因,采取如下工艺措施:在测温孔搭子处安放补缩冒口;适当加大浇注系统尺寸,浇注时间控制在13～17s;增加上型高度;加长砂芯芯头,等。结果总废品率由原来的50%降低到8.6%,因缩孔、气孔、冷隔造成的废品率由43.9%降低到5.9%。

The main reasons causing shrinkage cavity at the boss for temperature checking,as well as blowhole and cold lap in the jacket area between two straight pipes were analyzed.Following technological measures were adopted:setting a feeding riser at the boss for temperature checking,properly enlarging sections of the gating system,keeping pouring time in the range of 13～17 s,increasing height of cope mold,lengthening core prints,etc.As the result,the total rejection rate of the castings was reduced from original 50% to 8.6%,and the rejection rate caused due to the shrinkage cavity,blowhole and cold lap was reduced from 43.9% to 5.9%.