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一、问题的提出采用低压铸造方法生产铝合金汽车发动机缸盖(以下简称缸盖),在我国已有多年历史。缸盖本身结构复杂,壁厚相差太大。加之整个水套芯子被金属液包围,只有两端芯头上各设一个排气孔,排气条件不好。由于这些因素影响,缸盖在进行水压实验检查时出现渗漏,废品率较高。据了解,国内生产技术水平高的工厂,因渗漏造成的缸盖废品率在30%左右;生产技术水平较差的工厂废品率达40%,少数工厂高达60%以上。这不仅给国家造成了巨大浪费,而且严重地影响了汽车工业的发展。因此,研究低压铸造缸盖渗漏的成因,改进生产工艺,降低铸造废品率,是一件很有意义的工作。
First, the problem raised Low-pressure casting method of producing aluminum alloy engine cylinder head (hereinafter referred to as cylinder head), in our country has many years of history. Cylinder head itself complex structure, the wall thickness difference is too big. In addition, the entire water jacket core is surrounded by a liquid metal, and only one exhaust hole is arranged on each of the two core ends, and the exhaust condition is not good. Due to these factors, the cylinder head leaks during hydrostatic test, resulting in a high reject rate. It is understood that the high level of domestic production of factories, due to leakage caused by the cylinder head scrap rate of 30%; poor production technology factory scrap rate of 40%, a few factories up to 60%. This not only caused tremendous waste to the country, but also seriously affected the development of the automobile industry. Therefore, it is very significant to study the cause of leakage of cylinder head of low-pressure casting, improve the production process and reduce the rate of foundry rejects.