Machine Gray Cast Iron Gave Birth Process

Abstract: Considering the application properties, technical needs and frameworks of machine casts, the paper analyze the properties, specialties and suitable applying condition of different inoculums, the factors affecting cast properties and the inoculation's influence on the shape and growth of graphite and the affect of the graphite flake. New method of taking different inoculums and inoculation to achieve the different applied and technical conditions is presented in the machine cast of high ratio of C and Si. Various kinds of new inoculums and inoculations are studied, replacing the traditional way of only using FeSi75 to all conditions, to satisfy diverse property.The inoculation effects on castings, which causing by such inoculums as Fe-Si, Sr-Si, Ba-Si-Fe, C-Si-Ca and compound rare-earth are revealed, with deeply theoretical analyzing inoculation function of compound rare-earth.The machine, classifying as HT300, inoculated with Cr-Mn plus rare-earth, can achieve the σb at 300N/mm2 level or up, while the CrCu250 wearable cast, treated by Ca-Ba plus rare-earth, achieve theσb up 250 N/mm2. Theσb of cast of HT250 whose density is defined reaches 250 N/mm2 besides no leakage defects after treating by Sr-Si-Fe. The casts of small size which pouring time is longer than 10 minutes can be twice inoculated or inoculated by Ba-Si-Fe alloy to ensure the higher than 250 N/mm2 σb. All of the casts concerned here have processing property and regular rupture section so that completely reach the using standards of the machines, which also accompany the tendency of the machine cast of being delicate and light with thin wall, high strength.As a result, the machine property is more stable and compacted, with more economical profits achieved. The study of lighting the castings by way of inoculating high C.E ratio iron with compound inoculum is primary so that more research is still to be done.