Ductile Iron Lost Foam Casting Technology Development and Production Application about Medium and Small Sized Castings in China

摘要

The article focuses on the selection and research &development of foam material and casting process, andrnanalyzes the successful and failing cases in the application of lost foam casting of ductile iron, mainly for the following threernpoints: first, Chinese STMMA with stable quality and excellent briquettability is close to Japan in properties, and has beenrnused in more than 30 companies of ductile iron. Compared with the EPS, foam material of STMMA can significantly reducernthe carbon defects in ductile iron, thereby raise the percent of pass; second, ductile iron parts have been successfullyrnapplied in small and medium pieces of railway castings and auto parts (Brand QT450-10). Particularly in the small-scalernductile iron castings, string pouring process is used to improve the production yield (up to 80%) and production efficiency;rnthird, spheroidization level of ductile iron parts is low, mostly Grade three, Grade one or two few, making ductile iron inrnChina has a low-grade elongation. So, it is difficult to produce qualified products of Brand QT400-18. There are still somernproblems with ductile iron lost foam casting of China, such as flow mark, the carbon inclusions, and so on.