The functional behavior of the weldments is substantially determined by the nature of the weld strength characterized by the tensile strength, metallurgical behavior, surface roughness, weld hardness and micro hardness. In this project an attempt is made to determine and evaluate the influence of the process parameters of FSW on the weldments. The Vickers hardness, tensile strength and radiography are considered for investigation by varying tool speed, tool feed and maintaining constant depth of penetration of weld. Experiments were conducted on AA 6351 Aluminium alloy in a CNC Vertical Machining Centre (Make: Bharat Fritz Werner Ltd.) by programming for every experiment. The output factors are measured in UTM, Vickers hardness tester and Radio graphy equipment. Results show strong relation and robust comparison between the weldment strength and process parameters.