Effect of Strontium Modifier on Machinability Characteristics of Heat Treated A357 Alloy Using Statistical Techniques.

The current study sought to determine the influence of strontium addition on the microstructure and machinability of the A357 alloy. Furthermore, the influence of cutting parameters and aging temperatures on the machining performance of the modified alloy was investigated using a statistical technique. The machinability characteristics were investigated by milling experiments with a carbide tool. Experimental trials were carried out using Taguchi's L27 orthogonal array. Process parameters studied were strontium (Sr) percentage, aging temperature, cutting speed, and feed rate. Cutting force, surface roughness, and tool wear were investigated as responses. The microstructure of the specimens revealed that the addition of Sr to the A357 alloy helped to achieve refined grain structure. Furthermore, increasing the Sr concentration from 4 to 8% resulted in the enhanced refined microstructure. ANOVA analysis of responses revealed that Sr%, aging temperature, and feed rate have a significant effect on all the responses considered. However, cutting speed has exhibited the least influence. Further, the increase in Sr% resulted in an increase in cutting force and tool wear. Whereas, a decrease in surface roughness was observed due to increased Sr%. Whereas the increase of aging temperature, cutting temperature, and feed rate has resulted in the increase of response values. The aging temperature has shown significant influence on the variation of cutting force and surface roughness.. [ABSTRACT FROM AUTHOR]