The Study Of Key Technology On Vermicular Cast Iron Volume-Produce

Along with the power of load-carrying vehicle increased enlarging, diesel engine power increases continuously, the diesel engine cylinder head have to bear various increasing load, so the HT250and HT300graphite cylinder head which was produced by The yuchai machinery limited company’s foundry can not meet the produce quality control. Recently, the number of cylinder head crack malfunction was added continuously, which effected the dependability very much, lowed the satisfaction of consumer. Vermicular cast-iron has excellent hot transmit ability and high intension, so the research of vermicular cast-iron cylinder head was our emphases work.In this article we study on the effect of chemical element、vermicular agent、 vermiculizing process and vermiculizing ladle during the vermicular cast-iron cylinder head castvolume-produce. Explain the problem may occur during the vermiculizing. Through changing the gating system、putting cool iron or cool jacket on the thermal center、and improve the percentage of vermicular to solve the cylinder head shrinkage porosity and leakage. At the same time, we studied on adding tin in metal to improve the hardness of casting, and using normalizing process to save the under standard hardness casting. At last we can draw conclusion as followes:1、Chemical element especially the sulphur、carbon and chromium is very important to vermicular transact.2、Improve basic manage word, control material strictly, down the ratio of metal-coke, can get ideal low sulphur melt iron.3、Through changing gating system、putting cool iron and cool jacket on the thermal craft measures can improve shrinkage porosity problem.4、Through adding0.03%-0.08%tin in the melt iron, can improve the hardness of cast to HB160, and it’s handling characteristics will be better too.5、Through treated by normalizing process can saving under standard hardness casting.