An Investigation of Heat Affected Zone of Round Steel Rods Welded by Friction Welding

Friction welding is a welding technique that has been studied and developed continuously. This is due to its advantages, such as it provides high quality of joint, high strength of joint. It can make welded zone through the whole section without bubble. However, there is heat generated in the welding process that can change the phase of materials. Hence, the hardness and strength of joint are affected. This paper is aimed to investigate the microstructure at the joint, which is called heat affected zone. The experiment was conducted with a number of steel rods of 10 mm. diameter. The welded specimens were tested for strength, hardness and microstructure. The temperature gradient of specimen under welding process was also recorded. It was revealed that the strength of welded element is higher but the hardness is lower. The photo of thermo scan revealed that heat is generated around the lip of interface, resulting high temperature in heat affected zone. This causes some change in microstructure composition as well as joint property.