壳型生产曲轴的工艺改进

介绍了原来采用一型2件壳型工艺生产曲轴所遇到的问题,分析了采用一型4件壳型工艺在模具工艺布置的变化、喂丝球化替代冲入法球化、自动浇注机代替手工浇注等方面的技术难点,将铸造工艺设计为:将型板与固定架整体铸出,增加型板的强度,由原来的HT250改为热变形更小的H13模具钢;将直浇道直径由28 mm增大到38 mm,横浇道边长由24 mm提高到36 mm,形成封闭式浇注系统;改善凝固顺序;改善型壳的排气性。严格控制喂丝球化和浇注过程。最终综合废品率稳定在2%以下,各项力学性能均符合技术要求,并且在一汽大众以及上海大众进行了装车。

The Improvements on the Shell Mold Casting Technology of Crankshaft

The problems encountered in the production of crankshaft with one mold of two pieces of shell molding process was introduced. The technical difficulties of one mold of four pieces technique on the changes of mold,injection feeding spheroidization instead of conventional method and automatic pouring instead of manual pouring process were analyzed. The casting process was set as follows：the plate and the fixing frame was integrally casted,the plate strength was increased,H13 die steel was used instead of HT250;the diameter of sprue groove was increased from 28 mm to 38 mm and the side length of cross gate was increased from 24 mm to 36 mm,positive-pressure gating system was formed;the solidification progress and exhaustibility of molding shell were optimized. Along with strictly controlled injection feeding spheroidization and casting process,the reject ratio of final product was below 2% and mechanical properties meet the technical requirement. They were loaded on FAW Volkswagen and Shanghai Volkswagen autos.