球铁管件真空消失模壳型复合铸造工艺的研究

比较了真空消失模铸造和熔模铸造两种工艺的优缺点,将两种工艺的优点有机结合,开发了适应大量生产高性能出口管件的真空消失模壳型复合铸造工艺.介绍了消失模铸造模型刚度的确定、浇注系统尺寸的选择,壳型工艺流程的制订、壳型涂料的原材料选用和配制、以及水玻璃壳型制造流程.试验结果显示:(1)用此工艺生产的管件,工序简单且铸件质最稳定,铸件合格率达到98.5％以上；(2)此工艺只要制4层壳,相比普通蜡模精密铸造制壳要8层以上,提高了生产效率,降低了生产成本和人力资源成本.

Development of Vacuum Lost Foam-Investment Shell Mould Composite Casting Process Used for Ductile Iron Pipes Production

The advantages and disadvantages of the vacuum lost foam casting process and the investment casting process were compared. By combining two processes flexibly,a composite process consisted of vacuum lost foam process plus investment shell mould process and useable for large scale production of high property pipe castings was developed. An introduction was given to the determination of the rigidity of the lost foam pattern, dimensions choice of the gating system, establishment of the shell mould making process flow, the choice and preparation of the raw materials of shell mould, as well as the sodium silicate shell mould making process flow. The test result showed： （a）When using above process for the pipes production,the operation procedure was easy and the casting quality was stable with the casting pass rate higher than 98.5%; （b）This process needs only making 4 layers of mould shells, much less than that of the normal investment casting process which needs making 8 and even more layers of mould shells, and therefore, the productivity was enhanced ,both the production cost and the labors cost were reduced.