摘要
介绍了QT420-15牌号的6缸柴油发动机排气管的技术要求及缺陷特点。缺陷原因分析和试验结果表明:管壁有冷铁豆以及热节部位有缩松是造成排气管漏气的2个主要原因。采取了如下改进措施:(1)在浇口杯旁放置石棉条,堵塞滤网片与壳型之间的间隙,防止铁液进入间隙形成冷铁豆;结果漏气率从改进前的2.6%降低到0.5%以下;(2)加快2个搭子邻接部位的冷却速度,减少内浇道的铁液流量,砂芯做成空心形式,减小其发气量,适当降低浇注温度;结果 2个搭子邻接部位的漏气率由改进前的1.3%下降到0.6%以下。
The technical requirements and defects characteristics of QT420-15 grade nodular iron manifold used for 6-cylinder diesel engine were introduced. Defects reason analysis and experiments showed that cold iron beans existing in the pipe wall and the shrinkage porosities existing in the adjacent area between two neighboring bosses were the main reasons causing gas-leakage of the manifold. The following improving measures were adopted： （ 1 ）Setting asbestos ropes beside the pouring basin to block the gap between the filter and the shell mould and thereby to prevent the iron melt entering the gap to form the iron beans. As the result,the gas-leakage rate has been decreased from 2.6% before improvement to less than 0.5%.（2）increasing the cooling rate of the adjacent area between two neighboring bosses,reduce amount of the iron melt flowing through the ingates,making the core of the manifold hollow to reduce its gas evolution,properly decreasing pouring temperature. As the result,the gas-leakage rate in the adjacent area between two neighboring bosses has been decreased from 1.3% before improvement to less than 0.6%.
出处
《现代铸铁》
CAS
2014年第4期61-67,共7页
Modern Cast Iron
关键词
排气管
漏气
铁豆
缩松
manifolds
gas leakage
iron bean
shrinkage porosities
