Effect of green sand mixture with dextrin additives on mechanical properties of aluminum 6351

Abstract

Quality of cast produced from green sand mold is been influenced by mold properties which includes green compression strength, permeability, etc. In this work the green sand used for casting of aluminum 6351 alloy specimens were made by mixing in varied percentage proportions; bentonite clay, dextrin additive and moisture content with local silica sand considering the need for most effective proportions of these mixtures to enhance green sand production of aluminum 6351 alloy products. A 3 factor, 3 level (33) design of experiment (DOE) was made for this research work using Optimal (custom) design of Design-Expert 10 software which gave 20 runs. Cylindrical specimens for green sand test were prepared according to standard per run. This was in order to study effects of bentonite clay, dextrin additive and moisture content of the green molding sand used for casting per mold this aluminum 6351 alloy. Prepared sand specimens were individually subjected to basic sand test like green sand strength and permeability test and also cast specimens per mold achieved were subjected to mechanical property test to achieve results which become the Response output of the study. These experimental results were optimized for the purpose of achieving most effective proportions of the mixtures to give effective results and from the optimal validation values, 5% water content, 12% bentonite and 8.85182% dextrin organic additive was found to be the optimized solution that gave the most effective hardness at (40.4GSS and 112PN) while 3% water, 12% bentonite clay and 9% dextrin additive gave most effective toughness at (41.9GSS and 96.10PN).