Influence of Shot Peening Parameters on Surface Roughness and Micro Hardness Using DOE Technique

An engineered shot peened surface has potential surface applications. Peaks of the shot peening dimples helps to lower coefficient of friction and in some applications "valleys" of the peening dimples offer lubricant retentions that are not present in a smooth surface. Wear resistance of the component can be increased by controlling surface roughness, whereas by controlling surface hardness the fatigue life will increase due to the increase in cold work. Depending on the applicability of the component for fatigue or wear condition, the shot peened textured surface can be controlled, by setting the peening parameters based on the effect of individual, as well as interaction effect of the parameters. In this paper, full factorial Taguchi's 2^k DOE technique was used to analyze surface roughness and micro hardness, on the specimens made of medium carbon steel En8, using air blast type shot peening machine. This investigation examines the respective effects of influencing parameters such as pressure, shot size and the exposure time at their two different levels on surface roughness and hardness. After going through confirmation test the analysis reveals the right combination of the parameters for better process control. This technique sets an example for the other applications in the industries to reduce the performance variation and to improve quality, performance, reliability and profits.