Preparation effect of mould systems on microstructure and mechanical properties of spheroidised graphite iron
This study is based on evaluation of microstructure and mechanical properties such as tensile strength, Brinell hardness and Charpy impact test of as-cast spheroidal graphite iron using sandwich techniques in different mould systems viz. green sand mould, dry sand mould and CO2 sand mould under varying cooling rates.
The effects of foundry sand components on the cast iron
Article history: Received 11 Sep 2019 Revised 15 Jan 2020 Accepted 17 Jan 2020 Many studies are being carried out on factors such as casting temperature, cooling rate, mold design and, so on due to the effects of casting and solidification conditions on the mechanical properties of the final product. However, given literature, there appears to be no comprehensive study on the effect of casting mold sand components on the mechanical properties of cast iron. From this point of view within the scope of this study, the effects of casting mold sand and binder on the cast iron were investigated. By using silica and olivine as foundry sand at different ratios, bentonite and perlite as binders, the effects of them on the microstructure and the mechanical properties of casting were investigated. The microstructures of the products show that as the cooling rate slows down, the distribution of graphite particles in the structure changes from flakes to nodules. These structural changes are very matched with the results of mechanical properties. Therefore, when the cooling rate decreases, the hardness decreases from 310 HV to 239 HV in all of the groups. Also, the bending strength is going from 971.53 MPa to 487.42 MPa, like in the hardness results. On the contrary, the deformation increases from 13 % to 24 % when cooling rates decreases. This study clearly demonstrates that the products can be obtained by changing the heat conduction coefficient of the casting mold with different mechanical properties from the same molten metal.
Water Quality Aspects of Irrigation and Drainage: Past History and Future Challenges for Civil Engineers
This paper presents a brief history of irrigation and drainage related to ASCE activities on its Jubilee. This paper discusses legislation and policies that affect irrigation and drainage practices, water quality constituents of increasing concern in irrigation and drainage practices, and presents a prognosis on the future of declining freshwater resources available for irrigated agriculture and growing water quality problems in irrigation and drainage. Civil engineers in ASCE’s Irrigation and Drainage Division have compiled an 80-year history of highly meritorious service and accomplishments. In the next millennium, civil engineers will face a formidable challenge in managing and protecting the precious freshwater resources in the U.S.