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对4G22发动机气门座圈在生产过程中出现缩孔缺陷进行分析,从型壳的制作工艺、铸件的浇注工艺出发,找出缩孔缺陷的产生原因,并提出了相应的改进措施:一是提高型壳的焙烧温度,延长型壳的焙烧时间;二是采用红壳浇注,适当降低冷却速度;三是调整金属液出炉温度及浇注温度;四是适当提高浇注速度,缩短浇注时间。结果显示,改进生产工艺后,缩孔导致的缺陷率由原先的13%左右下降到3%以下。
The shrinkage defect of 4G22 engine valve seat was analyzed in the process of production. Based on the production process of the shell and the pouring process of the castings, the causes of shrinkage defects were found out, and the corresponding improvement measures were put forward. The first is to improve Second, the use of red shell casting, appropriate to reduce the cooling rate; Third, adjust the temperature of the molten metal and the casting temperature pouring; Fourth, an appropriate increase in pouring speed, shorten the pouring time. The results show that after the improvement of the production process, the defect rate caused by shrinkage cavities dropped from about 13% to below 3%.