18-10-2014, 01:54 PM
Abstracts: The objectives of this project is to Investigate General casting defects occurring in Metal casting of Spheroidal Graphite Cast Iron, and to minimize casting defects to the maximum possible extent in the rotor made up of Spheroidal Graphite Cast Iron (S.G. Iron), which will result in better, defect less quality and good production. Foundry industry suffers from poor quality and productivity due to the large number of Process parameters, combined with lower penetration of manufacturing automation and shortage of skilled workers compared to other industries. Casting defects result in increased unit cost. The defects need to be diagnosed correctly for appropriate remedial measures; otherwise new defects may be introduced. Unfortunately, this is not an easy task, since casting process involves complex interactions among various parameters and operations related to metal composition, methods design, molding, melting, pouring, shake-out and machining. The defects are classified in terms of their appearance, size, location, and consistency and inspection method. This helps in correct identification of the defects. For defect analysis, the possible causes are grouped into design, material and process parameters. Basically we have used three to four techniques for minimizing Casting defects found in Rotor made up of S.G. iron. So our aim is focused on type of metal rather than Component made up from that metal. Techniques like Riser pressurization and filling with tilting mold, Suggesting a nozzle shaped riser and many other necessary steps or methods have been carried out by us for minimizing defect to a reasonable extent. In the tilting molds metal is initially Poured into a holding basin in the mold and held for several seconds, in order to allow re-oxidation inclusions that form during pouring to grow and float to the top of the basin. Then the entire mold is tilted to transfer metal from the holding basin into the casting cavity, reducing air entrainment so less oxygen is brought into contact with the metal, and hence fewer inclusions form. Riser Pressurization is a Yield Improvement and Defect Reduction method. The aim of this Riser Pressurization method was to reduce shrinkage porosity defects in Spheroidal Graphite Cast Iron (S.G. Iron) castings. All techniques used by us here are trial and error based techniques. The use of these techniques can minimize the casting defects to a reasonable extent and can be helpful in production of sound and defect less Spheroidal graphite metal castings, which will increase casting yield.