Refining of the ausferritic microstructure will further enhance the mechanical properties of ADI and the presence of proeutectoid ferrite in the microstructure will considerably improve the ductility of the material. These combinations of properties are achieved by the microstructure consisting of acicular ferrite and high carbon austenite. The results are discussed in terms of fractographs, process variables and microstructural features of TSADI samples.ĭevelopment of Nanostructured Austempered Ductile Cast IronĪustempered Ductile Cast Iron is emerging as an important engineering materials in recent years because of its excellent combination of mechanical properties such as high strength with good ductility, good fatigue strength and fracture toughness together with excellent wear resistance. It has been observed from the wear studies that TSADI sample at 350Â☌ is showing better wear resistance compared to ductile iron. In acidic medium (H2SO4), the austempered samples showed better corrosive resistance compared to conventional ductile iron. The samples of Ductile Iron were austempered by the two-Step Austempering process at temperatures 300Â☌ to 450Â☌ in the steps of 50Â☌.Temperaturesare gradually increased at the rate of 14Â☌/Hour. Current work focuses on characterizing the two-step ADI samples (TSADI) developed by novel heat treatment process for resistance to corrosion and wear. Extensive literature survey reveals that it’s mechanical and wear behaviour are dependent on heat treatment and alloy additions. The two step austempering procedure helps in simultaneously improving the tensile strength as-well as the ductility to more than that of the conventional austempering process. Srisailam, Shravani Rao Ponangi, BabuĪustempered Ductile Iron(ADI) is an exciting alloy of iron which offers the design engineers the best combination high strength-to-weight ratio, low cost design flexibility, good toughness, wear resistance along with fatigue strength. Sliding wear and corrosion behaviour of alloyed austempered ductile iron subjected to novel two step austempering treatment Hardness is improved by austempering process. Hardness obtained in as cast DI is 28 HRC which decreased to 6 HRC in FDI due conversion of pearlitic matrix to ferritic matrix. Bulk hardness test was carried on Rockwell Hardness Tester with load of 150 kgf and diamond indenter. Ausferritic matrix coarsened (feathered) with increasing in austempering time for both DI and FDI. The area fraction of graphite remains unaffected due to austempering heat treatment. Area fraction of graphite was more in FDI than that of as cast DI. Area fraction of graphite, ferrite and austenite were determining using AXIOVISION-SE64 software. Austempering of ferritic ductile iron resulted in finer ausferrite matrix as compared to ADI. The austempered samples were characterized with help of optical microscopy, SEM and X-ray diffraction analysis. The samples were soaked in salt bath for 60, 120, 180, 240 and 300 min followed by air cooling. Both DIs were austenitized at 900Â☌ for 1h and then quenched into salt bath at 325Â☌. The new heat treated DI has graphite nodules in ferritic matrix and called as ferritic ductile iron (FDI). This heat treatment includes austenitization of DI at 900Â☌ for 1h, followed by furnace cooling to 750Â☌ & hold for 1h, then again furnace cooling to 690Â☌ hold for 2h, then samples were allowed to cool in furnace. The pearlitic matrix in DI was converted to ferritic matrix through heat treatment. The ductile iron (DI) has graphite nodules enclose in ferrite envelop in pearlitic matrix. Characterization of Austempered Ferritic Ductile Ironĭakre, Vinayak S.