精铸高性能珠光体铸态球墨铸铁开发与应用

Development and Application of Pearlite Matrix Ductile Iron with High Mechanical Properties in Precision Castings

论述了熔模精密铸造高性能珠光体铸态球墨铸铁QT800-5和QT700-8的开发和应用。确定了精铸高性能珠光体球墨铸铁低成本化学成分;开发出适合精铸球墨铸铁的低Mg高Ba包芯线和喂丝球化工艺,解决了小包球化不稳定的难题;摸索出适合于精铸球墨铸铁的三次孕育方式,解决了精铸球墨铸铁不具备后孕育条件下的孕育衰退难题;探索出适合于熔模精密铸造的共析冷却细晶强化措施,使精铸球墨铸铁的强度与伸长率得以兼顾。

This paper describes the development and application of as cast high performance pearlite ductile iron QT800-5 and QT700-8 by investment casting.Through a large number of experiments,the chemical composition of high-performance pearlite ductile iron produced by investment casting is determined to be different from that of sand cast ductile iron,and the production of high-performance ductile iron is realized at low cost.The low Mg and high Ba cored wire and wire feeding spheroidization process suitable for investment casting ductile iron were independently developed,which solved the problem of unstable spheroidization of small ladle of investment casting ductile iron.A special inoculation method suitable for investment casting was found,which solved the difficult problem of inoculation recession of investment casting ductile iron.The special eutectoid cooling fine grain strengthening measures of high-performance ductile iron have been explored,which makes it possible to give consideration to both strength and elongation of high-performance ductile iron.The recent four years of production and application show that the metallographic and mechanical properties of high-performance ductile iron have reached the technical requirements.