CADI - Carbidic Austempered Ductile Iron. Control structure in order to improve the tribological properties

摘要

Very high properties and advantages of Austempered Ductile Iron tend to develop an isothermal quenching process for this material especially to other its variation. One of the directions is to create and test a ductile iron tempered with isothermal transformation with controlled structure in which the graphite next to its spheroidal form there will be present in carbides. Such structure should significantly increase the already high erosion resistance of the alloy, which is used for machine parts and equipment working in particularly difficult conditions such as abrasive environment e.g. on agricultural tools for cultivation of the soil. Foundry Research Institute is performing research work with ductile iron tempered with isothermal transformation for many years. Among the varieties of this material in addition to the typical ADI cast iron the work was carried out on such variations as AGI, AVI, FADI, CADI, LCADI or MADI. The ability of surface hardening of ADI cast iron is a valuable feature of this material, after the wear of the hardened layer, another outer layer is progressively hardened. Further improvements of the properties may be obtained by creating the ausferrite structure and carbide eutectic in quantities of a few to several percent by entering carbide forming elements.