气缸盖铸造缺陷及防止方法

Defects and Prevention Methods of Cylinder Head

气缸盖的质量直接关系到柴油机的性能。针对新开发的某型气缸盖结构复杂,易产生缩孔、气孔等铸造缺陷,造成铸件渗漏的问题,从气缸盖铸件的技术要求出发,介绍了具体的生产设备、炉料配比、化学成分、工艺等生产条件。分析气缸盖铸件生产过程中缩孔、气孔产生的原因。结合操作现场的实际情况,通过优化铸造工艺,如设置冷铁、采用蓄热系数较高的铬铁矿树脂覆膜砂、适当降低浇注温度和速度、预先高温烘烤石墨芯、增加出气冒口等,有效地消除了相关缺陷,综合废品率控制在了3%以内。

The quality of cylinder head is directly related to the performance of diesel engine.In view of the complex structure of a newly developed cylinder head,which is prone to casting defects such as shrinkage holes and pores,resulting in leakage of castings,the specific production equipment,charge ratio,chemical composition,process and other conditions were introduced starting from the technical requirements of cylinder head casting.The causes of shrinkage holes and pores in cylinder head casting were analyzed.Combined with the on-site situation,the related defects were effectively eliminated by optimizing the casting process,such as setting the cold iron,using chromite resin coated sand with high heat storage coefficient,appropriately reducing the pouring temperature and speed,pre-baking graphite core at high temperature,increasing the gas vent,etc..And the comprehensive rejection rate was controlled within 3%.