铸造的双金属蜗轮与全铜蜗轮比较,有很多优点。它可以节约大量的铜合金;蜗轮的外缘是耐磨材料,内面是具有较高强度的钢或铸铁芯子,增强了蜗轮的使用寿命;内部的芯子起着冷铁的作用,有利于铸造。但在生产过程中,由于工艺选择不合理或操作不当时,会产生气孔等缺陷。我厂1980年以前,历年废品率均高达20％以上,其中气孔约占45％,渣孔约占25％,裂纹约占15％。针对这些缺陷我们做了很多实验,对一些主要影响因素采取了措施,使废品率降到5％以下,质量提高。双金属蜗轮的铸造工艺如图所示。 Casting bimetallic worm gear compared with the whole copper, there are many advantages. It can save a lot of copper alloy; the outer edge of the worm gear is wear-resistant material, the inside is a high strength steel or cast iron core, enhance the service life of the worm wheel; the inner core plays the role of chilled iron is conducive to Casting. However, in the production process, because the process of choice is not reasonable or improper operation, it will produce defects such as pores. Before 1980, the reject rate of our factory was as high as 20% or above, of which 45% were stomata, 25% were slag hole and 15% were cracked. In response to these defects we have done a lot of experiments, some of the main factors that have taken measures to reduce the rejection rate below 5%, improve quality. Bimetal worm wheel casting process as shown.