Effect Of Fly Ash Addition on Mechanical Properties of Al- 11 percent Si Alloy Castings Produced by V-Process

摘要

In almost all the major countries of the world, thermal power stations generating electrical power are getting bigger in size and are generating huge quantities of flyash as waste from their mammoth boilers. This flyash has to be disposed of without polluting the environment. Flyash utilization is a global problem and has attained complex dimensions with the passage of time commencing industrial revolution intensified by technological developments of twentieth century.Despite extensive research on flyash, its utilization level is poor although it is considered as a novel and useful material in various fields such as building and road construction, agriculture, refractory works, water treatment, foundry, etc. Countries likes U.S.A., Germany, Netherlands, etc. are utilizing 70 percent of flyash as building materials and for other useful purposes. Its utilization level in India is about 3-5 percent only.In this paper an attempt is made to visualize the effect of flyash, on the tensile properties of the Al-11 percent Si alloy castings produced by V-process. In order to evaluate the effect of flyash on the tensile properties of the V-process castings the response surface methodology (RSM) was used. The RSM was used to correlate the independent process parameters with the tensile properties by a mathematical model. The second order response surface was found suitable for the present work. The central composite design was used to plan the experiment.In addition to investigating the effect of flyash on the tensile properties, the effect of other process parameters, such as vi8brating frequency, duration of vibration, level of vacuum imposed, and pouring temperature, on tensile properties were also investigated.A multi-objective optimization model using the Goal programming approach has been developed and solved by Microsoft excel solver. It was found that flyash added to silica sand improved the tensile properties of the V-processed castings. The tensile strength improved from 154 Mpa (when there was no flyash) to 160 Mpa (when flyash addition was 50 percent). The percent elongation improved from 2.07 percent (no flyash addition).